48results about How to "To achieve the purpose of safe use" patented technology

The invention relates to a flame retardant antistatic toughening PVC (Poly Vinyl Chloride) pipe for methane. The pipe is produced and prepared by adding a nanometer strengthening and toughening material and an antistatic and fire retardant material to polyvinyl chloride resin. According to the flame retardant antistatic toughening PVC pipe for methane, the coordinative antistatic effects of alkyl sulfonic acid and conductive carbon black as well as the coordinative flame retardant smoke suppression effects of antimonous oxide, and tricresyl phosphate or aluminium hydroxide are fully utilized, so that the purpose of safely using the flame retardant antistatic toughening PVC pipe for methane in the methane transportation filed can be achieved along with the outstanding toughening and strengthening material. Compared with the traditional plastic pipe, the flame retardant antistatic toughening PVC pipe for methane has relatively high durable performance and relatively high safety, is specifically suitable for the fields of outdoor branch pipes for methane and home-entering introducing pipes, can effectively improves the safety in use, reduces the possibility that a pipeline is cracked and leaks gas due to an accidental impacting and the possibility that the pipeline causes an antistatic fire due to the reduced whole antistatic effect, cannot fuel the fire in case the fire occurs, generates little smoke, and reduces the risk of the fire to the affected residents and firefighters.

The invention provides a waterproof and damp-proof flat-plate solar collector, which comprises a plurality of frames, depression bars, sealing adhesive tapes, cover plates, bottom plates and connectors. The depression bars are disposed on the frames, each sealing adhesive tape is arranged between the corresponding frame and the corresponding depression bar, the cover plates are fixed by the aid of the sealing adhesive tapes, the bottom plates are laminated with the frames, and the connectors are connected among the frames. The frames are tightly laminated with the bottom plates, the connectors are independently arranged, accordingly, the problem of water leakage of frames of an existing flat-plate solar collector is solved, simultaneously, a layer of tin foil paper is adhered on each heat-insulation cotton and can effectively prevent water mist and water drops, the purpose of safe usage is achieved, instantaneous efficiency of the flat-plate solar collector is improved, an integral heat-insulation effect is enhanced, the service life is prolonged, and maintenance cost of the flat-plate solar collector is reduced.

The invention relates to a battery management system wake-up system and a DC / DC converter. Except for a power unit, the DC / DC converter also includes a control module which is connected to a battery management system and controls and connects the DC / DC power unit. When the battery management system needs to be woken up, the control module controls the DC / DC power unit to be turned on, so that a power battery can supply power to the battery management system. Otherwise, the control module controls the DC / DC power unit to be disconnected, and then the power battery does not supply power to the battery management system. The battery management system wake-up system can reduce the software and hardware cost of the battery management system and can improve the operational reliability of the battery management system. Besides, the DC / DC power unit does not need to work for a long time, so that the service life of the DC / DC power unit is prolonged, and as a power line between the DC / DC powerunit and the battery management system is no longer charged for a long time, the potential safety hazard for the whole vehicle can be reduced.

The invention discloses a military extra-high-pressure oxygen valve which comprises a sealing structure between a valve seat of a valve body and a valve clack. The sealing structure between the valve seat of the valve body and the valve clack is an angle-difference sealing pair with the angle difference ranging from 2 degrees to 5 degrees, and a valve stem is sealed to form a composite packing sealing structure. The military extra-high-pressure oxygen valve has the advantages that owing to the angle-difference sealing pair, an extremely narrow linear sealing belt is formed when two matched sealing surfaces are in contact with each other, high sealing specific pressure can be generated by means of applying extremely low sealing force, the military extra-high-pressure oxygen valve is excellent in sealing performance and low in driving force requirement, accordingly, requirements of extra-high-pressure industrial-grade pure oxygen under harsh and complicated working conditions in the aerospace field can be met completely, and the purpose of safety usage is achieved.

The invention relates to a safety infusion set which comprises a perfusion tube, a funnel and a pinhead. The perfusion tube is respectively connected with the funnel and the pinhead. A plastic foam floating ball is arranged in the funnel. As the structure is adopted, when the liquid in the funnel all comes out, the floating ball stems a liquid hole at the lower part of the floating ball, in this way even though the pinhead is not plucked off in good time, the blood in veins does not flow backwards into the infusion set, the purpose of safe use is achieved.

The embodiment of the invention relates to the technical field of electronics, and discloses a server, a power supply application method and a control device. In the embodiment of the invention, the power supply application method comprises the following steps: detecting the number of power supplies of a working power supply in a system and reading a system power value; if it is detected that thenumber of the working power supplies is at least two, and an abnormal trigger signal is received from the logic trigger module, obtaining an early warning power value according to a plurality of system power values; and if the early warning power value is greater than or equal to the power supply power value of the working power supply, outputting an abnormal processing signal to a control modulein the server through the logic trigger module, so that the control module reduces the processor power to a preset value and limits the system power to be within the maximum power of the working powersupply. According to the embodiment of the invention, under the condition that the system has a redundant power supply function, the cost is saved, the power supply utilization rate and the conversion efficiency are improved, the condition that the system oscillates can be avoided, and the purpose of safe use is achieved.

The invention provides an automatic control device of a handcart. The automatic control device comprises a supporting column (1), wherein the supporting column (1) is internally provide with a vertical through cavity (11); the through cavity (11) is internally provided with a rotary drum (7) capable of rotating; the rotary drum (7) and wheels (92) are mutually linked; the rotary drum (7) and central holes of the wheels are rotatably sleeved into wheel shafts (6); the circumference of the rotary drum (7) is provided with a radial inserting hole (74); the through cavity (11) is internally provided with an inserting rod (4) which can move up and down; the inserting rod (4) is connected with a pull rope (2); when the rotary drum (7) is rotated to the inserting hole (74) and is located below the inserting rod (4), the lower end of the inserting rod (4) can be inserted into the inserting hole (74); and a structure that the inserting rod (4) is pulled out from the inserting hole (74) can be arranged in the through cavity (11) through a pull rope (2). The automatic control device of the handcart disclosed by the invention has the advantages that whether the handcart is on a plane road surface or on an inclined slope road surface, the inserting rod in the supporting column can be automatically inserted into the inserting hole under the effect of no external force and the handcart can be automatically stopped; and therefore, the aim of safe utilization is realized.

The invention discloses a safety socket. The safety socket comprises a socket shell, a first sliding block stopper, a second sliding block stopper and a button part, wherein a first limiting structure is arranged between the button part and the first sliding block stopper, and a second limiting structure is arranged between the button part and the second sliding block stopper; movement of the button part to the socket shell is stopped through the first limiting structure and / or the second limiting structure so as to limit further insertion of a plug into the socket shell; or under a condition of recession of the first sliding block stopper and the second sliding block stopper due to an extrusion effect, stopping on the button part by the first limiting structure and the second limiting structure is removed. The safety socket provided by the invention has multiple protection effects, so that conditions of insertion of an unmatched plug into the socket and half insertion of the plug can be avoided; and meanwhile, the safety socket has the effects of electric shock prevention caused by mistake insertion, and water splashing prevention, and is reasonable in design, convenient to use, safe and higher in reliability, and capable of realizing safety in use.

The invention discloses a flame-retardant anti-static PVC (Polyvinyl Chloride) tube and a preparation method thereof. The flame-retardant anti-static PVC tube comprises the following raw materials: a polyvinyl chloride resin, a filling agent, a stabilizer, an impact modifier, a lubricant, an inorganic flame retardant and an anti-static agent, wherein the anti-static agent consists of calcined kaolin, conductive carbon black and titanium dioxide; and the inorganic flame retardant consists of brucite powder and sepiolite. The preparation method comprises the following steps: 1) mixing the filling agent, the inorganic flame retardant and the polyvinyl chloride resin for 2-5 minutes at a high speed; and 2) further adding the impact modifier, the stabilizer, the lubricant and the anti-static agent into the mixture of the step 1), mixing for 10-15 minutes at 100-110 DEG C, after uniform mixing, transferring into a cooling stirring, stirring for 3-5 minutes at 40-50 DEG C at a slow speed, and finally performing extrusion by using a conical two-screw extruder at 180-190 DEG C, thereby obtaining the tube. The tube is good in flame retardancy and anti-static property, and can be applied to fields such as marsh gases and coal.

The invention discloses a pulling device of a brake cable of a cart. The pulling device of the brake cable of the cart comprises a pressing block (1), a lever bar (2) and a casing pipe (3), wherein the lever bar (2) is arranged inside the inner cavity (41) of a push rod (4), the casing pipe (3) can move up and down to wrap the upper portion of the push rod (4), an opening (42) is formed in the top of the push rod (4), the lower portion of the pressing block (1) stretches into the inner cavity (41) of the push rod (4) through the opening (42) to be connected with one end of the lever bar (2) in a supporting mode, the other end of the lever bar (2) is connected with the brake cable (5), the lever bar (2) is movably connected with the push rod (4) through a rotary shaft (6), and the upper portion of the pressing block (1) is supported on the inner wall of the top surface of the casing pipe (3). The pulling device of the brake cable of the cart has the advantages that when the casing pipe on the push rod is held by the hand and is pressed downward automatically under the action of the gravity, the casing pipe moves downwards to drive the pressing block to be pressed downward, a brake core is pulled upward, and the cart can be moved front and back normally; when the push rod is disengaged from the hand, one end of the lever bar tilts upward due to the self-weight of the lever bar and the casing pipe is driven move upward to return to the original position, namely the brake part is automatically locked by the brake core.

The invention discloses a moving platform capable of constructing without colliding walls. The moving platform comprises a frame which is a cuboid integrally, four rollers are mounted at the bottom of the frame, two extension arms are mounted on a long edge of the top of the frame, a plurality of hanging rings are arranged on the extension arms, a counterweight disk is further arranged on the frame, and the counterweight disk and the extension arms are distributed in a body diagonal manner. By the rolling action of the rollers, the frame can be moved, so that moving of a hanging basket is realized and a movable operating platform is realized; and setting up of a large-scale scaffold at the bottom of an overhead viaduct is not needed, so that construction period is shortened and construction cost is lowered.

The invention discloses safety protection apparatus for a chemical reaction kettle, and relates to the technical field of chemical equipment. The apparatus comprises a fixing supporting plate, and a fixing clamping groove is fixedly connected with the middle position of the top of the outer surface of the fixing supporting plate; the surface of the concave part of the fixing clamping groove is seamlessly connected with a kettle body, a top cover supporting base seat is fixedly connected with one end far away from the fixing supporting plate, of the periphery of the outer surface of the kettlebody, and a safety protection device is arranged at the top of the top cover supporting base seat; and a movable supporting plate is fixedly connected with the middle position of the top of the innercavity of the fixing supporting plate. According to the invention, the safety protection apparatus for the chemical reaction kettle achieves the purpose of safe use, when a slide cover is opened, combined use of an exhaust fan and a mini-type pump is utilized, so that rapid cooling and gas exhausting are performed on the inner cavity of the reaction kettle, the operator is prevented from being burned by a high temperature or suffering from chemical corrosion, and the usage security of the chemical reaction kettle is improved.

The invention discloses a self-adaptive dual-gas-supply fuel gas warmer. The self-adaptive dual-gas-supply fuel gas warmer comprises a combustor, an ignition control assembly, a first ODS (oxygen depletion safety) protector, a second ODS protector, a main gas pipe, a first control valve and a second control valve, wherein the first ODS protector is applicable to natural gas; the second ODS protector is applicable to liquefied gas; the main gas pipe is separated into a pilot flame gas supply pipeline and a combustor gas supply pipeline after passing through a main control valve, the pilot flame gas supply pipeline is separated into a first pilot flame branch and a second pilot flame branch, and the combustor gas supply pipeline is separated into a first combustor branch and a second combustor branch; the first control valve is arranged on the first pilot flame branch and used for controlling opening and closing of the first pilot flame branch; and the second control valve is arranged on that first combustor branch and used for opening and closing of the first combustor branch. The self-adaptive dual-gas-supply fuel gas warmer has the advantages that by means of cooperation between the two control valves on the first pilot flame branch as well as the first combustor branch and the two ODS protectors, automatic judgment of gas supplies is achieved and corresponding pipelines can be opened or closed automatically during ignition.

The invention discloses a guide rail type mobile switch cabinet partial discharge on-line monitoring sensor, and belongs to the field of switch cabinet partial discharge on-line monitoring devices. The a guide rail type mobile switch cabinet partial discharge on-line monitoring sensor comprises a switch cabinet, a monitoring device, a first operation device and a second operation device. A cabinetdoor is arranged on the switch cabinet, the cabinet door is provided with a through opening, a handle is arranged on the cabinet door, the switch cabinet is connected with a clamping strip plate; thefirst operation device comprises a first rail and a second rail; the first rail and the second rail are both connected with clamping strip grooves, the clamping strip grooves are provided with threaded holes, the threaded holes are connected with screws, the first rail is provided with a motor power box, the first rail and the second rail are both provided with rail notches, the connecting rod penetrates through the rail notches, the connecting rod is provided with the second operation device, and the second operation device is provided with a monitoring device. The guide rail type mobile switch cabinet partial discharge on-line monitoring sensor is simple in structure and convenient to mount and dismount, and the effect that the guide rail type mobile switch cabinet partial discharge on-line monitoring sensor rapidly and conveniently performs partial measurement work is achieved.

The invention discloses a novel lightning protection overvoltage protection circuit and a protection device, A protection circuit includes a first varistor sheet, a second varistor sheet, a transientsuppression diode, a positive temperature coefficient thermistor sheet, a gas discharge tubes and a lead-out terminal, A first varistor sheet is connected in series with a gas discharge tube, A positive temperature coefficient thermistor chip is connected in series with a transient diode, and two series branches are connected in parallel with a second varistor chip in series to form a single-portcombined circuit, wherein, the performance of the first varistor chip and the gas discharge tube against surge shock is better than that of the second varistor chip against surge shock; At least one of the two lead-out terminals of the single-port combination circuit is a low thermal resistance thermal conduction terminal, the positive temperature coefficient thermistor sheet and / or the second varistor sheet are thermally coupled with the low thermal resistance thermal conduction terminal, and the transient suppression diode can be replaced with a zener diode or a voltage switching type element.

The invention relates to a flame retardant antistatic toughening PVC (Poly Vinyl Chloride) pipe for methane. The pipe is produced and prepared by adding a nanometer strengthening and toughening material and an antistatic and fire retardant material to polyvinyl chloride resin. According to the flame retardant antistatic toughening PVC pipe for methane, the coordinative antistatic effects of alkyl sulfonic acid and conductive carbon black as well as the coordinative flame retardant smoke suppression effects of antimonous oxide, and tricresyl phosphate or aluminium hydroxide are fully utilized, so that the purpose of safely using the flame retardant antistatic toughening PVC pipe for methane in the methane transportation filed can be achieved along with the outstanding toughening and strengthening material. Compared with the traditional plastic pipe, the flame retardant antistatic toughening PVC pipe for methane has relatively high durable performance and relatively high safety, is specifically suitable for the fields of outdoor branch pipes for methane and home-entering introducing pipes, can effectively improves the safety in use, reduces the possibility that a pipeline is cracked and leaks gas due to an accidental impacting and the possibility that the pipeline causes an antistatic fire due to the reduced whole antistatic effect, cannot fuel the fire in case the fire occurs, generates little smoke, and reduces the risk of the fire to the affected residents and firefighters.

A surge protector includes a varistor element, a gas discharge tube, a voltage limiting element, a heat-generating element and a heat-conducting terminal with low heat resistance, the heat-generatingelement is connected in series with the voltage limiting element and is connected in parallel with the varistor element, and the series-parallel branch circuit is connected in series with the gas discharge tube to form a single-port combined circuit, wherein, the performance of the varistor element to withstand surge shock is higher than that of the voltage-limiting element to withstand surge shock, and the varistor element's varistor voltage value is higher than that of the voltage-limiting element's on voltage value; one of the two lead-out terminals of the single-port combination circuit isa low thermal resistance thermal conduction terminal, which is thermally coupled with the heating element, or the low thermal resistance thermal conduction terminal is thermally coupled with the voltage limiting element, or the low thermal resistance thermal conduction terminal is thermally coupled with the gas discharge tube. The invention enables the SPD to exit the circuit in an open circuit mode and improves the safety.

The invention discloses a connecting structure of a charging interface, which is simple in structure and can reduce the manufacturing cost. The connecting structure comprises a plug and a socket, wherein the socket comprises a socket shell and a socket body installing seat which is arranged in the socket shell, and a connecting end of the socket shell is provided with a circular socket barrel; the plug comprises a plug body installing seat and a plug shell which is connecting with the plug body installing seat, a pulling preventing cover is movably sheathed on the plug shell and the plug body installing seat, the inner wall of the pulling preventing cover is provided with circumferential inner connecting threads and a limiting boss in sequence along the pulling-out direction, a circumferential in-place boss is arranged on the plug body installing seat, and the limiting boss and the inner connecting threads are positioned at two sides of the placing-in boss; and outer connecting threads which are matched with the inner threads are arranged on the outer wall of the circular socket barrel. By the mutual matching of the pulling preventing cover and the circular socket barrel of the socket shell, the connecting structure can achieve the purpose that the pulling by mistake is prevented, and eliminates potential safety hazards.

The invention discloses a novel surge protector, which includes a first varistor element, a second varistor element, a gas discharge tube, a heat-generating element and a heat-conducting terminal withlow heat resistance; The first varistor element and the heating element are connected in parallel to form a parallel branch, the second varistor element and the gas discharge tube are connected in series to form a series branch, and the parallel branch is connected in series with the series branch to form a combined circuit. The performance of the first varistor element to withstand surge shock is higher than that of the second varistor element to withstand surge shock. One of the lead-out terminals of the single-port combination circuit is a low thermal resistance heat conduction terminal, which is thermally coupled with the heating element, or the low thermal resistance heat conduction terminal is thermally coupled with the second varistor element, or the low thermal resistance heat conduction terminal is thermally coupled with the gas discharge tube.

A lightning-proof overvoltage protection circuit and a protection device are disclosed, A protection circuit includes a first varistor sheet, a second varistor sheet, a transient suppression diode, apositive temperature coefficient thermistor sheet and a lead terminal, A positive temperature coefficient thermistor chip and a transient suppression diode are connected in series and then connected in parallel with the first varistor chip, and the series-parallel branch circuit is connected in series with the second varistor chip to form a single-port combined circuit, wherein, the performance ofthe first varistor chip against surge shock is better than that of the second varistor chip against surge shock; At least one of the two lead-out terminals of the single-port combination circuit is alow thermal resistance thermal conduction terminal, the positive temperature coefficient thermistor sheet and / or the second varistor sheet are thermally coupled with the low thermal resistance thermal conduction terminal, and the transient suppression diode can be replaced with a zener diode or a voltage switching type element.

The invention provides a polypropylene pipe used for an underground coal mine. The polypropylene pipe is prepared from the following raw materials in parts by weight: 90 to 100 parts of polypropylene, 1 to 3 parts of barium sulfate crystal whisker, 3 to 12 parts of a fire retardant, 10 to 16 parts of an antistatic agent, 4 to 8 parts of a compatible material, 6 to 12 parts of a shock-resistant modifier, 0.6 to 1.2 parts of an antioxidant and 0.6 to 1.2 parts of a dispersing agent. The antistatic agent is prepared and obtained through the following method: dispersing conductive carbon black and acetylene carbon black into an appropriate amount of water to form dispersion liquid, adding glass fiber for dipping for 10 to 12 hours, and taking out to obtain the antistatic agent through baking. The polypropylene pipe has preferable antistatic property and fire resistance, and can be applied to the underground coal mine.

The invention discloses a big data computer network security protection device which comprises a heat dissipation box, a box body supporting plate and a protection box, a heat dissipation groove is formed in the upper portion of the heat dissipation box, a first heat dissipation motor is fixedly connected to the inner bottom face of the heat dissipation groove, a connecting block is fixedly connected to one side of the heat dissipation box, and a mounting block is fixedly connected to one side of the connecting block. A fixing hole is formed in one side of the mounting block, a threaded rotating rod is inserted into the fixing hole, and the outer surface of the threaded rotating rod is sleeved with a driven bevel gear. According to the big data computer network security protection device,through arrangement of the protection box, the big data computer network security protection device has the effect of protecting a computer, and through cooperative arrangement of the first heat dissipation motor, the first heat dissipation fan blades, the second heat dissipation motor, the second heat dissipation fan blades, the fire-fighting box, the fire-fighting pipe and the mounting strips, in the using process, the internal computer can be cooled and extinguished in time, so that the purpose of safe use is achieved.

The invention provides a push-and-pull type plug converter which is characterized by being fool-proof, small in size and portable. The plug converter mainly comprises a casing and two plug module groups, the two plug module groups move in and out of two sides, opposite to each other, in opposite directions respectively, each plug module group moves from an ineffective power-on position in the casing to an effective power-on position outside the casing along a sliding stroke of the module group itself, the two plug module groups slide in the casing in parallel, each plug module group is provided with a driving portion, and in the process that one plug module group slides from the ineffective power-on position to the effective power-on position, the driving portion of the plug module group approaches and abuts against the driving portion of the other plug module group, so that the other plug module group is pulled and moves from the effective power-on position to the ineffective power-on position. Thus, the fool-proofing function enables that only one conductive plug is pushed out.

The invention discloses an industrial grafting copolymerization blending modified PVC tubular product. The industrial grafting copolymerization blending modified PVC tubular product comprises 50 to 100 parts of grafting copolymerization polyvinyl chloride (PVC) resin, 2.0 to 3.0 parts of a stabilizing agent, 1 to 1.4 parts of a lubricant, 1.0 to 2.0 parts of a processing auxiliary agent, 3.0 to 6.0 parts of an impact modifier, 1.5 to 3 parts of a function modifier, 1.8 to 3.6 parts of a reinforcing agent, 0.01 to 0.05 part of a colouring agent, and 0.5 to 0.8 part of a fire retardant. According to a preparation method, full utilization of the high chlorine performance of grafting copolymerization polyvinyl chloride, the corrosion resistance of nanometer barium sulfate, and the cooperativeflame retardation smoke inhibiting effect of antimony oxide, tricresyl phosphate, or aluminium hydroxide is adopted, and an excellent toughening enhancing material is adopted, so that the industrial grafting copolymerization blending modified PVC tubular product is safe to be used in the fields of industrial corrosive medium conveying and fire-fighting water supply, and possesses corrosion resistance, flame resistance, internal pressure resistance, and impact resistance.

The invention discloses a lightning protection overvoltage protection device comprising a first varistor, a second varistor, a positive temperature coefficient thermistor, a gas discharge tube and lead-out terminals. The gas discharge tube is connected in series with the first varistor and then connected in parallel with the positive temperature coefficient thermistor. Then the series-parallel branch is connected in series with the second varistor so as to form a single port combination circuit. The surge withstand performance of the first varistor and the gas discharge tube is higher than that of the second varistor. At least one of the two lead-out terminals of the single port combination circuit is the low thermal resistance heat conduction terminal. The second varistor is coupled withthe positive temperature coefficient thermistor. The low thermal resistance heat conduction terminal is simultaneously and mutually thermally coupled with one or two of the second varistor and the positive temperature coefficient thermistor.

A surge protection circuit and a surge protection device are disclosed, A protection circuit includes a first varistor sheet, a second varistor sheet, a third varistor sheet, a positive temperature coefficient thermistor sheet, a gas discharge tubes and a lead-out terminal, A first varistor sheet is connected in series with a gas discharge tube, The positive temperature coefficient thermistor chipis connected in series with the third varistor chip, and two series branches are connected in parallel with the second varistor chip in series to form a single-port combined circuit. The performanceof the first varistor chip and the gas discharge tube against surge shock is better than that of the second varistor chip against surge shock. At least one of the two lead-out terminals of the single-port combined circuit is a low thermal resistance thermal conductive terminal, a second varistor sheet, a third varistor sheet and a positive temperature coefficient thermistor sheet form a thermal coupling, and the low thermal resistance thermal conductive terminal and the second varistor sheet and one or both of the positive temperature coefficient thermistor sheets are simultaneously thermallycoupled to each other.

The invention discloses a soup ladle, which belongs to the technical field of tableware. The soup ladle comprises a ladle handle and a ladle body connected with one end of the ladle handle, wherein the other end of the ladle handle is fixed with one end of an elastic pull rope; a ladle cover is arranged on the ladle body; the other end of the elastic pull rope is fixed to the center of the top of the ladle cover; and the joint of the ladle handle and the ladle body is provided with a rotating shaft connected with the ladle cover. The soup ladle with a ladle cover can prevent the soup from spilling over when the hand of a user shakes, thereby achieving the goal of safe use.

The invention discloses a high-safety surge protection circuit and a surge protection device. The protection circuit comprises a first voltage-sensitive resistor piece, a second voltage-sensitive resistor piece, a third voltage-sensitive resistor piece, a positive temperature coefficient thermistor piece and a leading-out terminal, wherein the positive temperature coefficient thermistor piece andthe third voltage-sensitive resistor piece are connected in series and then connected with the first voltage-sensitive resistor piece in parallel, the series-parallel branch circuit and the second voltage-sensitive resistor piece are connected in series to form a single-port combination circuit. The surge impact withstanding performance of the first voltage-sensitive resistor piece is higher thanthat of the second voltage-sensitive resistor piece. At least one of the two leading-out terminals of the single-port combination circuit is a low-heat-resistance heat conduction end. The second voltage-sensitive resistor piece and the third voltage-sensitive resistor piece form thermal coupling, and the third voltage-sensitive resistor piece and the positive temperature coefficient thermistor sheet form thermal coupling, and the low-heat-resistance heat conduction end and one or two of the second voltage-sensitive resistor piece and the positive temperature coefficient thermistor piece are thermally coupled with each other at the same time.

Provided is a brake device of a cart. A rolling element (7) capable of rotating is arranged in the middle of a through cavity (11), the rolling element (7) is linked together with a wheel (3), radial protruding portions (71) are distributed on the circumference of the rolling element (7), a notch (72) is formed between every two adjacent protruding portions (71), an inserting column (4) capable of moving upwards and downwards is arranged in the through cavity (11) in a supporting column (1) located above the rolling element (7), and the top of the inserting column (4) is connected with a pulling rope (2). When the rolling element (7) rotates to a position, below the inserting column (4), of the notches (72), the structure including that the lower end of the inserting column (4) can be inserted into one of the notches (72) and the inserting column (4) can be pulled out of the one of the notches (72) through the pulling rope (2) is arranged in the through cavity (11). The brake device of the cart has the advantages that whether the cart operates on a planar road surface or a slope road surface, as long as no external force acts, the inserting column in the supporting column can be automatically inserted into one of the notches, and the cart can be automatically stopped; accordingly, the purpose of safe using is realized.

The invention belongs to the field of medical injector, and specially relates to an injector capable of retracting the needle automatically, which comprises a needle barrel, a needle, a push-rod handle and a push-rod body. A piston sealed with an inner wall of the needle barrel is sleeved on the outer circumference at the upper end of the push-rod handle. The push-rod handle is provided on the lower end. The push rod is in a hollow structure. An annular convex shoulder converging inwards is formed on the upper end of the push-rod body. A chuck is disposed on the annular convex shoulder. A blind hole with an opening upward is arranged in the middle of the upper portion of the chuck. An annular concave slot is provided in the middle of the chuck and disposed in the inner cavity of the push-rod body. A spring capable for completely pulling the chuck into the inner cavity of the push-rod body is disposed in the inner cavity of the push-rod body. When the push-rod body is pushed to the bottom of the matched injector needle barrel, the needle of the injector abuts against the chuck, and the upper portion of the chuck is inserted into an end portion of the needle far away from a tip of the needle. The invention is simple in structure, convenient for use, low in cost, easy for large scale production, and suitable for the injector capable of retracting the needle automatically.