43results about How to "Addressing Durability Issues" patented technology

The invention discloses a vacuum absorption rubbing type separating and fetching mechanism and a vacuum absorption rubbing type separating and fetching method. The vacuum absorption rubbing type separating and fetching mechanism comprises an absorption rubbing mechanism, a lifting mechanism, a horizontal moving mechanism and a detection mechanism, and is characterized in that the absorption rubbing mechanism comprises a wide type finger cylinder clamping jaw, suction nozzle seats are respectively mounted on the left and right sides of the clamping jaw, four suction nozzles are respectively mounted on the suction nozzle seats, and an inclined suction nozzle is arranged in the middle of the right suction nozzles; the wide type finger cylinder clamping jaw is fixed below the lifting mechanism; the lifting mechanism comprises a lifting rack and is driven to lift by using a cylinder with a guide rod; the horizontal moving mechanism comprises a movable block provided with two sets of moving guide rods and guide sleeves, the lifting mechanism is driven to horizontally move by using a movable cylinder, and the detection mechanism gives signals to actuate actions of the parts. According to the invention, with the adoption of vacuum suction of eight suction nozzles and inclined suction nozzle and mask rubbing of driving the suction nozzles to suck by using the wide type finger cylinder clamping jaw, effective separation of masks is realized, and the problem that an automatic mask folding machine is not stable, reliable and durable in mask suction and separation is well solved.

The invention relates to a preparation method of a special function textile fiber. The special function textile fiber comprises a functional device and a high polymer material fiber layer coating theperipheral face of the functional device. The method comprises the following steps that 1, a high polymer material is manufactured into a preform rod, the preform rod is processed so that a hollow cavity can be formed inside, and the hollow cavity is filled with a functional material to form the rear packaging end of the functional device; or, the high polymer material is composited with the functional device inside a mold after being softened, and after extrusion molding, the high polymer material fiber layer is formed on the peripheral face of the functional device; 2, the preform rod obtained in the step 1 is stretched to obtain the special function textile fiber. The functional material distribution can be structurally controlled, the function effect can be effectively improved, meanwhile, functional raw materials can be saved, and the cost is effectively lowered; the problems that an existing prepared fiber is not high in durability and low in functionality efficiency are solved.

The invention relates to an angle grinder which comprises a gearbox, a rotor, a rotor front bearing, a rotor rear bearing, a bearing box, an output shaft, an output shaft bearing and a lock pin, wherein one end of the output shaft is fixedly connected with a grinding wheel piece of the angle grinder by penetrating through the bearing box, and the other end is fixedly connected with a big gear; the big gear is meshed with a small gear fixed on a rotor front end shaft; the outer side of the rotor rear bearing is connected with a wild shield and a stator; both the wild shield and the stator are sleeved on a rotor front end shaft; elastic oil seals are additionally arranged between the rotor front bearing and the rotor front end shaft and between the output shaft bearing and the output shaft respectively; O-shaped seal rings are respectively sleeved on the lock pin of the gearbox and an end cover opening of the bearing box approaching to the side of the gearbox; a bearing aluminum sleeve is sleeved on the periphery of the rotor rear bearing; and a dust preventing ring is arranged between the rotor rear bearing and a rotor rear end shaft. The invention can effectively prevent dust, dissipate heat, reinforce the seal performance of the gearbox and prolong the service life of the bearings and the durability of gears.

The invention relates to a power battery packet, which comprises an anode plate (a bus-bar), a cathode plate (a bus-bar) and a plurality of batteries, wherein the batteries are cylindrical or rectangular or cubical monomer batteries, and are welded between the anode plate and the cathode plate in the way of connection in parallel. The invention is characterized in that an anode terminal is led out from one end of the anode plate through the flow ways such as current and the like, and a cathode terminal is led out from the other end of the cathode plate in the reverse direction. The invention can be designed in W / h according to the vehicle-mounted space, and can be conducted with the effective connection in parallel or in series of expansion and split W / h according to the requirements, which is suitable for the transformation of vehicles with various types and purposes. The invention realizes 5C discharge and charge, can charge in 15 minutes, and has 1700 times of service life and 80% DOD, which fundamentally solves the conflict of cost performance and safety and durability, and solves the technical problems that world battery industry manage to solve.

The invention discloses a concrete box type building module, a modular assembly type building and a construction method of the modular assembly type building. The problems that traditional building construction is large in labor demand, long in construction period, large in material waste, large in construction waste and serious in pollution, an existing fabricated building is high in cost and low in prefabrication rate, and an existing concrete modular building technology is incomplete and the structural safety is poor are solved. A prefabricated reinforced concrete structure box-type building module capable of bearing a room function is included. The modular building structure method is jointly achieved through vertical through type slurry anchor connecting cavities in a wall body, transverse connecting steel plates on the edge of a top plate, mortar bonding between modules, through snap-in grooves and the like. And the box-type building module is integrally duplicated by using the mold, so that the construction efficiency is improved. The modules are connected and constructed outside the box-type building modules, and the high prefabrication rate of decoration is guaranteed. Factory processing is achieved, and the building quality is reliable. Connecting components and main body steel bars are integrated, stress is scientific and reasonable, and fire resistance, shock resistance and durability are good.

The invention provides a fast cage type tobacco clamp for a bulk curing barn. A technical scheme of the invention is as follows: a support frame is arranged on two ends of an L-shaped bracket, a movable cover is connected with the L-shaped bracket through a hinge such that the movable cover can rotate, the movable cover after folded is tightly clung on the support frame, contact pins are respectively lapped on lower edges of square holes of the L-shaped bracket and the movable cover after a tobacco fork is inserted, and the tobacco fork and the movable cover are stably clamped on the support frame by using a clip. According to the fast cage type tobacco clamp disclosed by the invention, the tobacco loading efficiency can be largely increased, links of roasting tobacco leaves and technical complexity can be reduced, the labor saving effect is remarkable, and tobacco growers can get rid of complex tobacco weaving links; in addition, the difficulties of poor roasting effect of the prior tobacco clamp and complex and short-life structure of the tobacco clamp are solved at the same time; and when the fast cage type tobacco clamp is matched with a bulk curing barn for use, the volume and the roasting capability of the bulk curing barn can be increased on the premise of ensuring the roasting quality, which is very important to expanding planting scale of each family and factory and professional roasting.

The invention discloses a screw pump with low viscosity and high pressure. The screw pump comprises a pump body, a driving screw, a bearing and a sealing structure, wherein the driving screw, the bearing and the sealing structure are arranged in the pump body. A driven screw is further arranged in the pump body. The bearing and the sealing structure are arranged on the driving screw in a sleeving manner. A pump cavity is formed in the pump body, and a bushing is arranged in the pump cavity in the axial direction. The driving screw and the driven screw are arranged in the bushing which is provided with matching holes. The side wall of the driven screw is in engaged fit with the side wall of the driving screw, and the two ends of the side wall of the driven screw are connected with the top inner wall and the bottom inner wall of the pump cavity correspondingly. The bottom of the driving screw is arranged over the bottom inner wall of the pump cavity. The screw pump with low viscosity and high pressure is simple in structure, small in size, compact in layout, convenient to install, durable, resistant to abrasion, high in pressure and low in internal leakage of flow, the abrasion resistance and durability of the engaged screw pair and the surface of the inner wall of the bushing can be effectively enhanced, power energy consumption can be reduced, and the service life can be prolonged.

The invention provides a water-cooled commercial stove energy-saving hearth. The water-cooled commercial stove energy-saving hearth at least comprises a hearth body, a furnace end, a fuel nozzle, an air blower and a premixed fuel pipe, wherein the hearth body wholly takes the shape of an inverted cone, and at least comprises a hearth body inner wall, a hearth body outer wall and an annular hollow water channel; the furnace end at least comprises a furnace end inner wall, a furnace end outer wall, a furnace end gas pipe, a furnace heart and an ignition needle; a cavity enclosed by the furnace end inner wall is an inner cavity; the furnace end outer wall encloses the furnace end inner wall; a cavity between the furnace end outer wall and the furnace end inner wall is an outer cavity; and the top end of the premixed fuel pipe is connected with the furnace end gas pipe, and the bottom end of the premixed fuel pipe is connected with the fuel nozzle and the air blower. The hearth solves the problems of no durability and potential safety hazard caused by high temperature in a conventional metal cast hearth; and meanwhile, the water-cooled commercial stove energy-saving hearth, provided by the invention, also can produce hot water, so that the efficiency is preferably improved.

The invention discloses a 430 antibacterial stainless steel cladding knife and a preparation method thereof. The 430 antibacterial stainless steel cladding knife comprises the following chemical components in percentage by weight: less than or equal to 0.12% of C, less than or equal to 1% of Si, less than or equal to 1% of Mn, less than or equal to 0.04% of P, less than or equal to 0.03% of S, 16%-18% of Cr, 1%-3.5% of Cu, less than or equal to 2.5% of Mo, less than or equal to 0.035% of N, larger than or equal to 0.03% and less than or equal to 0.06% of C+N, larger than or equal to 0.04% andless than or equal to 0.14% of Ti+Nb+V, one or more of following alloy elements of Ti, Nb, Mo, V, Zr, Sn and Sc and the balance Fe and impurities, wherein the percent of each of Ti, Nb, Mo, V, Zr, Snand Sc is less than or equal to 1%. The comprehensive performance of the 430 antibacterial stainless steel cladding knife prepared through the method far exceeds that of a traditional martensitic steel knife, the problems that the traditional knife is healthy and safe in food contact, permanently resistant to corrosion and rust, sharp and durable are solved, and on the basis of the 430 antibacterial stainless steel knife, the laser cladding technology is used for improving the wear resistance and the sharpness of a finished cutting edge.

The present invention relates to a gas boiler, and particularly to an energy-saving high-efficient gas normal-pressure boiler. The energy-saving high-efficient gas normal-pressure boiler of the invention settles the problems of large gas consumption, insufficient burning, low thermal efficiency and inferior durability existing in the prior gas boiler. The energy-saving high-efficient gas normal-pressure boiler comprises the following components: a boiler housing, a fire tube, an inner container of a hearth, an outer container of the hearth, an inner face plate, the hearth surrounded by the inner container of the hearth, a water interlayer which is surrounded by the fire tube, the inner container of the hearth, the outer container of the hearth and the inner face plate, a first vortex combustion chamber and a second vortex combustion chamber that are respectively provided at the front end and the back end in the boiler housing. The fire tube is sleeved with a water tube with both ends communicated with the water interlayer. The two ends of the water tube are provided with the outer face plates which have edges fixed with the side wall of the inner container of the hearth and are used for supporting the water tube. The energy-saving high-efficient gas normal-pressure boiler of the invention reduces the gas consumption amount while increasing the usage factor of the heat energy of the fuel, and is a novel gas boiler which has the advantages of energy saving and environment protecting.

The invention discloses a steel ladle composite building method and a compositely-built steel ladle. The compositely-built steel ladle comprises a work layer and a top sealing material; the inner side wall and the outer side wall of the work layer and the inner side wall and the outer side wall of the top sealing material are unfolded to be in an annular fan shape; the diameter of the upper end of the top sealing material is larger than the diameter of the upper end of the work layer; annular-fan-shaped slag line bricks are connected to the inner side of the upper end of the work layer; an annular-fan-shaped packing layer is connected to the outer side of the upper end of the work layer; the slag line bricks are flush with the upper end of the packing layer; and the top sealing material is connected to the upper ends of the slag line bricks and the upper end of the packing layer. Steel ladle building is conducted through a slag line magnesia carbon brick and alumina-magnesia spinel castable composite technology, the steel ladle has the advantages of both long service life and low cost, and the requirements for the safety and economical efficiency in the steel ladle refining process are met.

The invention relates to the field of high-voltage switch equipment, in particular to a disconnecting grounding switch mechanism, switch equipment and a guide contact base of the disconnecting grounding switch mechanism. The guide contact base comprises a base body and a disconnecting switch moving contact base arranged on the base body, a guide hole used fro being horizontally formed in the disconnecting grounding switch mechanism is formed in the base, an opening in one end of the guide hole is used for facing the connecting-in direction of a main circuit connecting-in conducting structure, an opening in the other end is used for facing the inserting direction of a disconnecting switch moving contact, and a mutual inductor connecting terminal is further arranged on the base body. The problem that an existing guide contact is prone to causing large occupied space and inconvenient assembly and disassembly of the disconnecting grounding switch mechanism is solved.

The invention relates to the technical field of building external sunshade, in particular to a sunshade window capable of achieving multi-angle adjustment. The sunshade window capable of achieving multi-angle adjustment comprises an upper window fixing beam, a lower window fixing beam, a left window side plate, a right window side plate, a sun louver, a hand switch and a folding sheet. According to the sunshade window capable of achieving multi-angle adjustment, when in hot summer, the sun louver is unfolded, and the sun louver can steer freely according to different solar altitudes and azimuth angles. In short, the sun louver on the sunshade window capable of achieving multi-angle adjustment can be freely unfolded and rotated according to the requirement for temperature and sunlight, andthe window conforms to the design philosophy for modern energy-saving buildings. In addition, a sealing rubber strip and a waterproof strip in the sunshade window capable of achieving multi-angle adjustment can achieve the sealing and waterproof functions in an auxiliary mode, rainwater can be prevented from entering a room due to the included angle formed between the horizontal plane and the upper plate of the lower window fixing beam, the angle of the sun louver can be more convenient to adjust by adopting the push rod motor, and the sunshade window capable of achieving multi-angle adjustment is multifunctional, wide in application range, convenient to use and suitable for being used and popularized.

The invention discloses a preparation method of a zirconia-based metallic ceramic material. The preparation method comprises the following steps that 1, a designed amount of iron metal powder and a designed amount of zirconia-based ceramic powder are taken and mixed into powder, and a primary mixture is obtained; 2, compression molding is conducted, and a compressed blank is obtained; 3, the obtained compressed blank is dried and subjected to heat preservation; 4, vacuum sintering is conducted, and a semi-finished product is obtained; and 5, the obtained semi-finished product is ground, subjected to finishing and dried, and then the zirconia-based metallic ceramic material is obtained. According to the preparation method of the zirconia-based metallic ceramic material, the problems that ametallic ceramic heat exchange pipe in a traditional preheating furnace is not durable and poor in heat exchange efficiency are mainly solved, the problems that the traditional heat exchange pipe is short in service life and low in heat exchange efficiency are solved by compounding the zirconia-based metallic ceramic material with the good heat conductivity and elongation and improving a traditional production technology, and the zirconia-based metallic ceramic material is especially suitable for being applied to a gas-phase preheating furnace with the preheating temperature being 800 DEG C or above.

The invention discloses an electromagnetic wave type micro casting and liquid forging integrated 3D metal printing machine. The electromagnetic wave type micro casting and liquid forging integrated 3Dmetal printing machine comprises a traditional 3D sand mould printing machine (1), an electromagnetic wave rapid melting metal filling device (4), a micro casting and liquid forging pressure device (5) and an integrated electronic controller (3), wherein a target piece sand mould (2) is printed by the traditional 3D sand mould printing machine (1). A part 3 comprises a master controller (MCU), apulse generator (PG), a solid-state relay (SR), a temperature controller (CNTL) and a converter (TR); a part 4 comprises a nozzle (NZ), a crucible (CR), an electromagnetic wave inductor (EM), a liquidmetal or liquid metal based composite (LQ), a temperature sensor (TS), a ball valve (BV), an exhaust hole (EX) and an electromagnetic valve 1 (E1); and a part 5 comprises compressed gas (A) and an electromagnetic valve 2 (E2). The electromagnetic wave type micro casting and liquid forging integrated 3D metal printing machine achieves dense uniform structure of a workpiece, grain refinement, excellent mechanical property and high anti-fatigue degree of metal, and solves the problems that the cost of the conventional metal 3D printing is high, the labor hour is long and no durable material is printed.

The invention relates to the technical field of motors, in particular to a motor shaft. The motor shaft comprises a shaft body, and is characterized in that the shaft body comprises a first half shaft and a second half shaft, wherein external threads are formed at the rear end of the first haft shaft; internal threads corresponding to the external threads are formed at the front end of the second half shaft; the first half shaft is connected with the second half shaft through the internal and external threads; knurls and ceramic membranes are arranged on peripheral surfaces of both the first half shaft and the second half shaft. The motor shaft is convenient for motor assembly and can improve the assembly efficiency.

A durable pigmented film, particularly intended for use in lieu of or as a replacement for conventional paint, is a composite film having a thickness of from about 1 to about 20 microns and comprised of a polymer matrix containing from about 15 to about 50% by volume of pigment particles. Methods of making and using the film are disclosed.

The invention discloses a hydraulic-balance screw pump assembly. The hydraulic-balance screw pump assembly comprises a drive screw and a driven screw which is engaged with and adaptive to the drive screw; and a liquid flowing hole which penetrates through the whole rod is axially formed in the driven screw. The hydraulic-balance screw pump assembly can effectively solve the problems that a current screw pump assembly is not wear-resisting and durable, is relatively high in power, is great in energy consumption and is short in service life due to the fact that axial force and radial centrifugal force of the driven screw are too great after a screw pump works and boots.

The invention relates to a cloth processing method, in particular to a method for forming a grid cloth by folding. Grid patterns can be formed by folding and sewing up a whole cloth, so the toughness of a textile can be enhanced greatly, thereby being used for manufacturing products such as bags and the like. By adopting the folding mode, the formed interlaced grid pattern has strong third dimension, and suture joints can be hidden to achieve good appearance; and the grid cloth is thin in thickness, light in weight and is better in product texture compared with leather, because a hot melt adhesive tape is not required in the forming process. In the grid pattern forming process, the steps of cutting the cloth into small square pieces and adhering the small square pieces are not required, thus greatly reducing the processing steps, being environment-friendly and ecological, maintaining the original cloth texture and solving the problems of strength and duration when the cloth is used for manufacturing bags.

The invention discloses an automatic cleanser adding device for a closestool in order to solve the problems that a traditional closestool cleanser is expensive and is not durable. The automatic cleanser adding device for the closestool comprises a container and a solution; the automatic cleanser adding device is characterized in that the container is formed by drilling a plurality of small holes in the upper part of the bottom part of a common waste plastic bottle and is used for containing a cleanser and enabling the cleanser to flow out automatically; the solution is prepared from a detergent prepared by people in advance and is used for cleaning dirt in the closestool. According to the automatic cleanser adding device for the closestool, disclosed by the invention, by refitting common articles around, the efficiency of adding the cleanser to the closestool is increased, the expenditure in people's life is saved, convenience is provided for people's life, the preparation is simple, and the use is convenient.

The invention discloses a high-precision dropper used for chemical industry. The high-precision dropper comprises a liquid accumulating cavity, wherein the interior of the liquid accumulating cavity is movably connected with an extrusion plate; the upper surface of the extrusion plate is fixedly connected with a connecting column which penetrates through the interior of the liquid accumulating cavity and extends toward the outside; one end of the connecting column is fixedly connected with a hand press plate; the bottom part of the hand press plate is fixedly connected with a spring; one end of the spring is fixedly connected with the upper surface of the liquid accumulating cavity; the bottom part of the liquid accumulating cavity is fixedly connected with an inclined plate; the positionof the center of the inclined plate is provided with a liquid accumulating opening; and the bottom end of the liquid accumulating opening is fixedly connected with a straw. The high-precision dropperprovided by the invention has the following advantages: the effects of liquid suction and liquid discharging through upward-and-downward movement in the liquid accumulating cavity are achieved; the drive power for the extrusion plate to continuously move up is reached; the effect of liquid suction is improved; the action of fixing the straw is reached; the precision of the dropper can be effectively reinforced; the problem of incapability of reaching the liquid accumulating cavity for the extrusion plate due to the height of the spring can be effectively reduced; and the problems of durabilityand precision of the dropper are effectively solved.

The invention discloses a boat stern driving system and a hydraulic clutch. The boat stern driving system comprises an engine arranged in an engine cabin of the boat stern, a hydraulic clutch connected with the power output end of the engine, and a stern connected with the output end of the hydraulic clutch; a power input shaft of the hydraulic clutch is connected with a power output shaft of the engine; an output shaft of the hydraulic clutch is connected with the stern; the hydraulic clutch comprises a connecting part which is used for connecting the output end of the engine, a power input shaft which is positioned on one side, far from the engine, of the connecting part and connected with the power output shaft of the engine through the connecting part, a forward gear clutch arranged on the power input shaft, a reverse clutch which is arranged on one side, far from the engine, of the connecting part, a hydraulic shift component and an output shaft. The boat stern driving system and the hydraulic clutch are low in manufacture cost, and are convenient to maintain and assemble.

The invention discloses a preparation method and application of an oil-water separation membrane based on an oxime urethane bond, and belongs to the field of material preparation. The preparation method of the oil-water separation membrane based on the oxime urethane bond of the present invention takes the synthesis of the compound containing the oxime urethane bond and the polyvinylidene fluoride as the solute, and the spinning solution with N,N-dimethylformamide as the solvent is passed through electrostatic The nanofiber oil-water separation membrane was prepared by spinning. The different contents of compounds containing oxime urethane bonds and polyvinylidene fluoride can control the fiber structure of the nanofibers and the size under the microscopic morphology, and because the oil-water separation membrane has pores It can be used for the separation of organic solvent and water because of its characteristics and hydrophobicity; the reaction conditions of the invention are mild, the synthesis process is simple, the energy consumption is small, and the post-treatment is simple and green. The invention solves the problems that the nanofiber material consumes a lot of energy during the preparation process and cannot be prepared on a large scale.

The invention relates to a cloth processing method, in particular to a method for forming a grid cloth by folding. Grid patterns can be formed by folding and sewing up a whole cloth, so the toughness of a textile can be enhanced greatly, thereby being used for manufacturing products such as bags and the like. By adopting the folding mode, the formed interlaced grid pattern has strong third dimension, and suture joints can be hidden to achieve good appearance; and the grid cloth is thin in thickness, light in weight and is better in product texture compared with leather, because a hot melt adhesive tape is not required in the forming process. In the grid pattern forming process, the steps of cutting the cloth into small square pieces and adhering the small square pieces are not required, thus greatly reducing the processing steps, being environment-friendly and ecological, maintaining the original cloth texture and solving the problems of strength and duration when the cloth is used for manufacturing bags.

The invention relates to a preparation method and application of nano-particle functionalized artificial spider silk. The preparation method comprises the steps that nascent artificial spider silk is taken as a template, nano-particles are prepared in situ through chemical reaction, and nano-functionalization of spider silk is realized; specifically, recombined spider silk protein nascent fibers are soaked in an ion solution, and nucleation sites of the nano-particles are formed through ions in combination with protein molecular chains in the nascent fibers in advance; and the artificial spider silk is soaked by adopting a composite ion solution, and in-situ synthesis is carried out on the nano-particles which are uniformly dispersed and uniform in particle size in the artificial spider silk. The preparation method is simple and convenient, the produced composite fiber contains nano-particles which are small in particle size and uniformly dispersed, the mechanical property of the fiber can be further improved through nano functionalization, and the toughness of the fiber exceeds that of natural spider traction fibers; and meanwhile, after multiple times of water washing and drying, the functional properties of the composite fiber are almost not affected, and different kinds of nano-particles can be prepared in the fiber, so that the requirements of people on fiber materials in different scenes are met.

The invention discloses an austenitic stainless steel turning technique. In metal cutting processing, the stainless steel material belongs to a difficult processed material and the austenitic stainless steel material is especially difficult to process. The cutting technique, processing cost and processing quality of the austenitic stainless steel all become the present machining problems. Through continuous exploring and searching, the optimum tool geometric angle, material, cutting liquid, and the like are confirmed; a test analysis method is adopted for confirming the method of the austenitic stainless steel turning technique; the austenitic stainless steel turning technique has the characteristics of short time, accuracy, reliability and strong pertinence; through analysis and comparison, reasonable technical parameters are acquired; an experimental result proves that the problems of large turning force, high cutting temperature, low tool durability and low production efficiency during the austenitic stainless steel turning process can be better solved; the quality of the workpiece is obviously increased; the problem of difficulty in cutting the austenitic stainless steel is basically solved.

A ridge-shaped combined building structure comprises stand columns, a cross beam, cant beams, eave assemblies, ridge assemblies, triangular tie pieces, purlins, tiles, an awning and the like. The novel combined steel structure building is created by integrating metal material science, architectural mechanics and plastic technologies and has the following advantages: the structure is firm and safeto use; the structure is free of welding and rapid and convenient to mount; the structure is detachable and recyclable; fixed assets can be changed into movable assets by position change; the structure occupies small space and is convenient to storage and transport after dismounting; the structure is suitable for standard and industrial production; the span is 2-7.5 m and the length can be increased; the structure is widely applied to temporary or permanent warehouses, garages, tents, pergolas, solar greenhouses, breeding greenhouses and the like.

The invention provides a hydraulic pressure revolving shaft, which comprises a shell, a piston, a transmission shaft, at least two passages and elastic plugging parts, wherein a sealing cavity is formed in the shell; liquid is filled in the sealing cavity; the piston divides the sealing cavity into a first chamber and a second chamber; the transmission shaft passes through the piston and is screwed with the piston, and is extended out of the shell; the at least two passages are communicated with the first chamber and the second chamber; the size of one end of each of the passages is reduced gradually and the orientations of the passages are opposite to each other; the elastic plugging parts are used for plugging the passages; when the rotating force applied to the transmission shaft is smaller than a predetermined value, the passages are plugged, and the transmission shaft cannot rotate; and when the rotating force applied to the transmission shaft is greater than the predetermined value, the plugging parts are compressed, the passages are opened and the transmission shaft rotates.