After more than a year of repeated tests and cooperation with seven other collaborators, the high-performance steel team of Shanghai University School of Materials successfully developed the world’s first 19.8-grade ultra-high-strength bolt known as the world’s strongest fastener.contemporaneity Hub bolt Our competitors have not made large-scale improvements, so we should get ahead of everyone in the project. https://www.chinatianlong.com/

　　Through the optimization of materials and heat treatment process, the tensile strength of 16.8 and 19.8 grade bolts at room temperature meets 1600~1770MPa and 1900~2070MPa respectively.

　　The results of shear test (according to GJB 3376-1998) show that the shear force of grade 16.8 and grade 19.8 bolts reaches 97KN and 115KN respectively.

　　The tensile fatigue strength test at room temperature (according to GJB 3376-1998 and GJB715.30A-2002, the load ratio =0.1) shows that the developed fastener meets the fatigue life requirements (the average fatigue life is not less than 65,000 times, and the single fatigue life is not less than 45,000 times).

　　The results of delayed fracture resistance test (according to GJB 715.12-1990, the constant tensile stress was kept for 96 hours in atmospheric environment) showed that the bolt did not break during the test time, and no cracks were found on the bolt surface and thread after unloading. The comprehensive performance of the newly developed ultra-high strength bolt meets the service requirements.

　　Class 16.8 and 19.8 fasteners in kind (specifications are MJ8〜1〜50)

　　Under the same clamping force, the ultra-high strength fastener can reduce its weight and increase the installation space by reducing its own size, so it can optimize the function and volume of the connected parts, so as to achieve the goal of overall weight reduction and performance optimization of the equipment.

　　So what is a high strength bolt? What is the strength of high-strength bolts? Sister Jin brought you here today to find out.

　　one

　　What is a high strength bolt?

　　High-Strength Friction Grip Bolt, literally translated as: high-strength friction preload bolt, abbreviated as HSFG. It can be seen that the high-strength bolt mentioned in Chinese construction is the abbreviation of high-strength friction pre-tightening bolt. In daily communication, only the words “Friction” and “Grip” are briefly mentioned, but it has caused many engineers and technicians to understand the basic definition of high-strength bolts, resulting in misunderstandings.

　　Myth 1:

　　Bolts with material grade over 8.8 are “high strength bolts”?

　　The core difference between high-strength bolts and ordinary bolts is not the strength of the materials used, but the form of stress. The essence is whether to apply pre-tightening force and use static friction to resist shear.

　　In fact, there are only two kinds of high-strength bolts (HSFG BOLT) mentioned in British Standard Specification and American Standard Specification (BS EN 14399/ASTM-A325&ASTM-490), while ordinary bolts include 4.6, 5.6, 8.8, 10.9, 12.9, etc. (BS 3692 11, Table 2) It can be seen that the strength of materials is not the key to distinguish high-strength bolts from ordinary bolts.

　　2?

　　Where is the strength of high-strength bolts?

　　According to GB50017, calculate the tensile and shear strength of a single ordinary bolt (Class B) with Grade 8.8 and a high-strength bolt with Grade 8.8.

　　Through calculation, we can see that the design values of tensile strength and shear strength of ordinary bolts are higher than those of high-strength bolts under the same grade.

　　So where is the “strength” of high-strength bolts?

　　In order to answer this question, it is necessary to study the law of elastic-plastic deformation of two kinds of bolts from the design working state, and understand the limit state of design failure.

　　Stress-strain curves of ordinary bolts and high-strength bolts under working conditions

　　Limit state of design failure

　　Ordinary bolt: the screw itself has plastic deformation exceeding the design allowable, and the screw is sheared.

　　For ordinary bolted connections, there will be relative slip between the connecting plates before they begin to bear shear force, and then the bolt rod will contact with the connecting plates, which will cause elastic-plastic deformation and bear shear force.

　　High-strength bolt: The static friction between the effective friction surfaces is overcome, and the two steel plates are relatively displaced, which is considered as failure in design.

　　When high-strength bolts are connected, the friction bears the shear force first. When the load increases to the point where the friction force is not enough to resist the shear force, the static friction force is overcome and the connecting plates slide relatively (limit state). However, although it is damaged at this time, the bolt rod is in contact with the connecting plate, and it can still bear the shear force by using its own elastic-plastic deformation.

　　Myth 2:

　　High bearing capacity is high strength bolt?

　　From the calculation of a single bolt, it can be seen that the design strength of high-strength bolt in tension and shear is lower than that of ordinary bolt. The essence of its high strength is that during normal operation, the joint is not allowed to slip, that is, the elastic-plastic deformation is small and the joint stiffness is large.

　　It can be seen that the joints designed with high-strength bolts may not necessarily save the number of bolts under the given design node load, but they have small deformation, high stiffness and high safety reserve. It is suitable for the main beam, and other positions that require greater joint stiffness, which conforms to the basic seismic design principle of “strong joints and weak members”.

　　The strength of high-strength bolts lies not in the design value of their own bearing capacity, but in the high stiffness, high safety and strong damage resistance of their designed joints.

　　three

　　Comparison between high strength bolts and ordinary bolts

　　Ordinary bolts and high-strength bolts have great differences in construction inspection methods because of their different design stress principles.

　　The mechanical performance requirements of ordinary bolts of the same grade are slightly higher than those of high-strength bolts, but high-strength bolts have one more acceptance requirement for impact work than ordinary bolts.

　　The marking of ordinary bolts and high-strength bolts is the basic method to identify bolts of the same grade on site. Because the values of torque calculation for high-strength bolts in British and American standards are different, it is necessary to identify the bolts of the two standards.

　　Ordinary bolts are about 70% of the price of high-strength bolts. Combined with the comparison of their acceptance requirements, it can be concluded that the premium part should be to ensure the impact energy (toughness) performance of materials.

　　A simple example is similar to the behavior of “wearing a mask” in the past, which will be called strange. Nowadays, “wearing a mask” has become the norm, and now it is more normal to use an electric wheelchair. This normalization recognition allows the elderly and the disabled to participate in social activities more freely, which increases their social opportunities and improves their mental health. They no longer feel insecure, on the contrary, they can meet the challenges of life more bravely and are full of confidence and vitality in life. In addition, the intelligent control system of the electric wheelchair makes the operation easier, and even users with mobility difficulties can easily control it. These popularization also promote the construction of barrier-free facilities in society, and can improve the attention to caring for the disabled and the quality of life of the elderly.Down-to-earth right 電動輪椅價錢 In-depth research is the only way to pursue development. https://www.hohomedical.com/collections/light-weight-wheelchair

　　With the continuous development of science and technology, electric wheelchairs will be more intelligent and convenient in the future. Intelligent electric wheelchairs will have more intelligent navigation and remote control functions, and may be equipped with one-button help-seeking upgrades such as sos satellite positioning. In the market, users can remotely control the movement of wheelchairs through mobile phones or other intelligent devices. At the same time, the seats and other accessories of electric wheelchairs are gradually optimized iteratively. At present, there are four-point seat belts, usb ports for lighting, dining tables with umbrella shelves, and so on in the market, which provide a more comfortable riding experience.

　　Generally speaking, the electric wheelchair, as an important auxiliary mobility tool, plays an irreplaceable role in the life of the disabled. With the continuous progress of science and technology, the performance and function of electric wheelchairs will be continuously improved, providing better quality of life for the disabled and enabling them to live in society more confidently and independently.

　　The world’s cutting-edge walking machine is difficult to process intramedullary nails with internal threads!In order to facilitate users to have a better experience, rock nut Many attempts have been made to upgrade the products, and the results are also very good, and the market performance tends to be in a good state. https://www.chinatianlong.com/

　　I. Overview of Bone Nail

　　Bone nail, also known as fracture fixation screw, is often used as a fixed orthopedic implant in clinic. Bone nails are usually used to fix internal fractures or dislocations. By directly screwing in two different bone blocks or fixing bone plates and other internal implants, the fractures can be fixed, the bones can be positioned and their healing can be promoted. Bone nails are widely used, including shoulder, elbow, hip, knee, spine and other major areas. For example, pedicle screw system is used for spinal fusion, and compression bone screws are usually used for foot and ankle surgery or other fixation of fractures under pressure. Yao Ming, Duran and other famous stars have implanted bone nails.

　　Second, the main structure of bone nail

　　Similar to traditional mechanical screws, the main structure of bone nail also includes nail cap, nail body and nail tip.

　　Schematic diagram of main structure of bone nail

　　Three, according to the screw function classification

　　Bone screws can be divided into plate screws, tension screws, position screws, interlocking screws and reduction screws according to their different functions.

　　Table 1. Function Classification of Screws

　　Several common screws

　　Fourth, bone nail materials change with each passing day

　　Traditional bone nails are mainly made of two materials, stainless steel and titanium. With the advent of new biodegradable biomaterials, more and more materials are used to make bone nails.

　　(1) Bioabsorbable screws

　　At present, although Chinese enterprises still mainly promote basic products, new degradable bone nails are being actively developed and put into the market. In recent years, more bone nails made of absorbable materials have entered the market and achieved good clinical results.

　　Common absorbable screws (left: PLA absorbable screws; Right: magnesium bone nail)

　　(2) Coated screws

　　In addition to manufacturing materials as a whole, many companies have also begun to study the surface coating of screws, thus increasing the surface wear resistance and hardness of bone nails and reducing the effect of material rejection. For example, Nail PROtect, launched by DePuy Synthes, an orthopedic materials giant, claims to have the effect of preventing infection.

　　Nail PROtect

　　(3) Biological bone nail

　　At present, there is no manufacturer producing biological bone material in China, but the excellent biological performance and postoperative rehabilitation effect of biological bone material are better than any artificial implant. The good biocompatibility of biological bone nail does not need to worry about rejection and secondary surgery. Researchers at the University of Graz in Austria have developed an allogenic orthopedic screw and named it shark screw, which has been clinically applied in 14 hospitals in Austria. Although the problem of bone donation needs to be solved in addition to processing technology, with the enhancement of Chinese people’s awareness of donation and the current situation of China’s population base, it is believed that biological bone materials also have huge market potential.

　　Shark screw

　　It is expected that the relevant enterprises in China’s bone nail industry will start from the details, concentrate on research and development, pay attention to innovation, and take advantage of the policy dividend, and small screws can also raise hundreds of millions of markets ~

　　Wheelchairs are widely used in patients’ rehabilitation training and family life, such as lower limb dysfunction, hemiplegia, paraplegia below the chest and people with mobility difficulties. As patients’ families and rehabilitation therapists, it is very necessary to know the characteristics of wheelchairs, choose the most suitable wheelchairs and use them correctly.If you want to make a big difference in the market, 電動輪椅價錢 It is necessary to intensify the upgrading of products on the original basis in order to meet the consumption needs of consumers. https://www.hohomedical.com/collections/light-weight-wheelchair

　　First of all, what harm will an inappropriate wheelchair do to the user?

　　Excessive local compression

　　Form a bad posture

　　Induced scoliosis

　　Causing contracture of joints

　　(What are the unsuitable wheelchairs: the seat is too shallow and the height is not enough; The seat is too wide and the height is not enough)

　　The main parts that wheelchair users bear pressure are ischial tubercle, thigh, popliteal fossa and scapula. Therefore, when choosing a wheelchair, we should pay attention to whether the size of these parts is appropriate to avoid skin wear, abrasions and pressure sores.

　　Let’s talk about the choice of wheelchair, which must be kept in mind!

　　Choice of ordinary wheelchair

　　Seat width

　　Measure the distance between two hips or between two legs when sitting down, and add 5cm, that is, there is a gap of 2.5cm on each side after sitting down. The seat is too narrow, it is difficult to get on and off the wheelchair, and the hip and thigh tissues are compressed; The seat is too wide, it is difficult to sit still, it is inconvenient to operate the wheelchair, the upper limbs are easy to get tired, and it is difficult to get in and out of the gate.

　　Seat length

　　Measure the horizontal distance from the hip to the gastrocnemius of the calf when sitting down, and reduce the measurement result by 6.5cm. The seat is too short, the weight mainly falls on the ischium, and the local pressure is easy to be too much; If the seat is too long, it will compress the popliteal fossa, affect the local blood circulation, and easily irritate the skin of this part. It is better to use a short seat for patients with extremely short thighs or flexion and contracture of hips and knees.

　　Seat height

　　Measure the distance from the heel (or heel) to the popliteal fossa when sitting down, and add 4cm. When placing the pedal, the board surface should be at least 5cm from the ground. The seat is too high for the wheelchair to enter the table; The seat is too low and the ischium bears too much weight.

　　seating washer

　　In order to be comfortable and prevent pressure sores, a seat cushion should be placed on the seat, and foam rubber (5~10cm thick) or gel cushion can be used. To prevent the seat from sinking, a piece of plywood with a thickness of 0.6cm can be placed under the seat cushion.

　　Backrest height

　　The higher the backrest, the more stable it is, and the lower the backrest, the greater the range of motion of the upper body and upper limbs. The so-called low backrest is to measure the distance from the seat surface to the armpit (one arm or two arms extend forward horizontally), and subtract 10cm from this result. High backrest: measure the actual height from the seat surface to the shoulder or back pillow.

　　Handrail height

　　When sitting down, the upper arm is vertical and the forearm is flat on the armrest. Measure the height from the chair surface to the lower edge of the forearm, and add 2.5cm. Proper armrest height helps to maintain correct posture and balance, and can make the upper limbs placed in a comfortable position. The armrest is too high, and the upper arm is forced to lift up, which is easy to fatigue. If the armrest is too low, you need to lean forward to maintain balance, which is not only easy to fatigue, but also may affect your breathing.

　　Other auxiliary parts of wheelchair

　　Designed to meet the special needs of patients, such as increasing the friction surface of the handle, extending the brake, anti-shock device, anti-skid device, armrest mounting arm rest, wheelchair table to facilitate patients to eat and write, etc.

　　Bolt looseness is common, but if you don’t pay attention, it will often cause equipment vibration, component damage, and even casualties. How to tighten a small nut has always been a long-lasting topic in mechanical design. Today, let’s talk about the most basic method of fixing nuts in work.Before that, mining nut The market has also soared for a time, which has attracted the attention of a wide range of investors. https://www.chinatianlong.com/

　　In general, we analyze the bolt fracture from the following four aspects:

　　First, the quality of bolts

　　Second, the pre-tightening torque of bolts

　　Third, the strength of bolts

　　Fourthly, the fatigue strength of bolts.

　　In fact, most cases of bolt fracture are caused by looseness, specifically, it is damaged due to looseness. Because the situation of bolt loosening and breaking is basically the same as that of fatigue fracture, finally, we can always find the reason from the fatigue strength. In fact, the fatigue strength is so great that we can’t imagine it, and the fatigue strength is not used at all in the use of bolts.

　　01

　　The bolt fracture is not due to the tensile strength of the bolt.

　　Take a M20〜80 8.8-grade high-strength bolt as an example. Its weight is only 0.2kg, and its minimum tensile load is 20t, which is as high as 100,000 times its own weight. Under normal circumstances, we only use it to fasten 20kg parts, and only use one thousandth of its maximum capacity. Even under the action of other forces in the equipment, it is impossible to exceed 1,000 times the weight of the parts, so the tensile strength of threaded fasteners is sufficient and it is impossible to damage them because of insufficient strength of bolts.

　　02

　　The fracture of bolts is not due to the fatigue strength of bolts.

　　Threaded fasteners can be loosened only 100 times in the transverse vibration loosening experiment, but they need to be vibrated repeatedly for one million times in the fatigue strength experiment. In other words, the threaded fastener is loose when using one ten thousandth of its fatigue strength, and we only use one ten thousandth of its great capacity, so the loosening of the threaded fastener is not due to the fatigue strength of the bolt.

　　03

　　The real reason for the damage of threaded fasteners is looseness.

　　When the threaded fastener is loosened, it generates huge kinetic energy mv2, which directly acts on the fastener and equipment, causing the fastener to be damaged. After the fastener is damaged, the equipment cannot work in a normal state, further causing the equipment to be damaged.

　　When the fastener is subjected to axial force, the thread is damaged and the bolt is pulled off.

　　When the fastener is subjected to radial force, the bolt is cut and the bolt hole is oval.

　　04

　　Choosing thread locking mode with excellent locking effect is the fundamental solution to the problem.

　　Take hydraulic hammer as an example. The weight of GT80 hydraulic hammer is 1.663 tons, and its side bolts are 7 sets of M42 bolts of grade 10.9. The tensile force of each bolt is 110 tons, and the pre-tightening force is half of the tensile force, and the pre-tightening force is as high as 300 to 400 tons. However, the bolt will break, and now it is ready to be changed to M48 bolt. The fundamental reason is that the bolt locking cannot be solved.

　　When a bolt breaks, it is easy for people to conclude that the strength is not enough, so most of them adopt the method of increasing the strength grade of the bolt diameter. This method can increase the pre-tightening force of the bolt, and its friction force is also increased. Of course, the anti-loosening effect can also be improved, but this method is actually a non-professional method, and its investment is too large and its income is too small.

　　In short, the bolt is: “If you don’t loosen it, it will break.”

　　Cause analysis of bolt looseness

　　The threaded connection is designed according to the self-locking condition: ψ ＋ρv, and the friction pair generated in the threaded pair makes the bolt self-lock to tighten the bolt, so the connection will not loosen automatically under static load. However, under impact, vibration, variable load and great temperature change, the friction force f of the screw pair will decrease or disappear instantly. If this phenomenon occurs repeatedly, the connecting bolt will gradually loosen. After the threaded fastener is loosened, the kinetic energy mv2 is generated, and the fastener subjected to axial force, the thread is destroyed and the bolt is pulled off. Fasteners subjected to radial force, bolts are cut and bolt holes are broken.

　　Bolt locking principle: limit the relative motion between screw pairs or increase the difficulty of relative motion.

　　Introduction of common anti-loosening methods

　　There are three commonly used methods for locking bolts: friction locking, mechanical locking and permanent locking. Among them, mechanical locking and friction locking are called detachable locking, while permanent locking is called non-detachable locking.

　　01

　　Friction locking

　　1. Spring gasket locking

　　The anti-loosening principle of the spring washer is that after the spring washer is flattened, the spring washer will generate a continuous elastic force, so that the threaded connection pair between the nut and the bolt will maintain a friction force continuously and generate a resistance moment, thus preventing the nut from loosening. At the same time, the sharp corner at the opening of the spring washer is embedded into the surface of the bolt and the connected piece respectively, thus preventing the bolt from rotating relative to the connected piece.

　　2. Lock the top nut (double nut)

　　3. Self-locking nut locking

　　One end of the nut is made into a non-circular convergent or radially convergent after being slit. When the nut is tightened, the closure expands, and the screwing threads are pressed by the elastic force of the closure.

　　4. Locking of elastic ring nut

　　Fiber or nylon is embedded in the thread to increase friction. The elastic ring also plays a role in preventing liquid leakage.

　　02

　　Mechanical locking

　　Locking of groove nut and cotter pin

　　2. Stop gasket

　　After the nut is tightened, the single-ear or double-ear stop washer is bent and attached to the side of the nut and the connected part respectively to realize locking.

　　3. Locking of series steel wire

　　Use low-carbon steel wire to penetrate the holes in the head of each screw, and connect the screws in series to brake each other.

　　03

　　Permanent locking

　　Commonly used permanent locking are: spot welding, riveting, bonding, etc. This method mostly destroys threaded fasteners during disassembly and cannot be reused.

　　In addition, there are other ways to prevent loosening, such as: coating liquid adhesive between screwing threads, embedding nylon rings at the end of nuts, riveting and locking. Mechanical locking and friction locking are called detachable locking, while permanent locking is called non-detachable locking.

　　1, punching method to prevent loose

　　After the nut is tightened, the thread is damaged at the end of the thread.

　　2. Adhesive Locking-Nut Locking Solution

　　Apply the nut locking liquid to the bolt tightening position, and then screw on the nut. After self-curing, the locking effect is good.

　　When choosing the frame material, we should not only consider the material itself, but also pay attention to the design and function of the frame. For example, folding electric wheelchairs bring great convenience to those who are inconvenient to bend over or have disabled hands, so that they no longer have to work hard to fold electric wheelchairs; The conventional electric wheelchair is comprehensive, affordable and stable, suitable for a wider range of users.We have every reason to believe. 電動輪椅價錢 It will become the mainstream of the industry and will gradually affect more and more people. https://www.hohomedical.com/collections/light-weight-wheelchair

　　Front wheel and rear wheel: The design of front wheel and rear wheel of electric wheelchair directly affects its flexibility and shock absorption. Usually, an electric wheelchair has four wheels, two of which are front wheels (universal wheels) and the other two are rear wheels (driving wheels). The smaller the front wheel, the more flexible the wheelchair is, which is suitable for turning flexibly in a narrow space. However, the smaller front wheels are easy to fall into ditches or ground cracks when facing them, which affects the driving experience. In addition, the size of the front wheel also affects the climbing ability of the electric wheelchair. The larger front wheel makes it easier for the wheelchair to climb the stairs, which makes it more convenient for users in their daily lives.

　　Shock absorption: the choice of tires is also very important in shock absorption. The tires of electric wheelchairs are usually divided into pneumatic tires and solid tires. Pneumatic tires have good shock absorption, and it is not easy to feel bumpy when passing through ditches and ridges, while solid tires will feel strong shock when facing uneven roads. In addition, some electric wheelchairs are equipped with special shock absorbers, which makes the driving more stable. These designs not only improve the comfort of wheelchairs, but also make users safer when they are outdoors.

　　The world’s cutting-edge walking machine is difficult to process intramedullary nails with internal threads!In combination with these conditions, Auto parts It can still let us see good development and bring fresh vitality to the whole market. https://www.chinatianlong.com/

　　I. Overview of Bone Nail

　　Bone nail, also known as fracture fixation screw, is often used as a fixed orthopedic implant in clinic. Bone nails are usually used to fix internal fractures or dislocations. By directly screwing in two different bone blocks or fixing bone plates and other internal implants, the fractures can be fixed, the bones can be positioned and their healing can be promoted. Bone nails are widely used, including shoulder, elbow, hip, knee, spine and other major areas. For example, pedicle screw system is used for spinal fusion, and compression bone screws are usually used for foot and ankle surgery or other fixation of fractures under pressure. Yao Ming, Duran and other famous stars have implanted bone nails.

　　Second, the main structure of bone nail

　　Similar to traditional mechanical screws, the main structure of bone nail also includes nail cap, nail body and nail tip.

　　Schematic diagram of main structure of bone nail

　　Three, according to the screw function classification

　　Bone screws can be divided into plate screws, tension screws, position screws, interlocking screws and reduction screws according to their different functions.

　　Table 1. Function Classification of Screws

　　Several common screws

　　Fourth, bone nail materials change with each passing day

　　Traditional bone nails are mainly made of two materials, stainless steel and titanium. With the advent of new biodegradable biomaterials, more and more materials are used to make bone nails.

　　(1) Bioabsorbable screws

　　At present, although Chinese enterprises still mainly promote basic products, new degradable bone nails are being actively developed and put into the market. In recent years, more bone nails made of absorbable materials have entered the market and achieved good clinical results.

　　Common absorbable screws (left: PLA absorbable screws; Right: magnesium bone nail)

　　(2) Coated screws

　　In addition to manufacturing materials as a whole, many companies have also begun to study the surface coating of screws, thus increasing the surface wear resistance and hardness of bone nails and reducing the effect of material rejection. For example, Nail PROtect, launched by DePuy Synthes, an orthopedic materials giant, claims to have the effect of preventing infection.

　　Nail PROtect

　　(3) Biological bone nail

　　At present, there is no manufacturer producing biological bone material in China, but the excellent biological performance and postoperative rehabilitation effect of biological bone material are better than any artificial implant. The good biocompatibility of biological bone nail does not need to worry about rejection and secondary surgery. Researchers at the University of Graz in Austria have developed an allogenic orthopedic screw and named it shark screw, which has been clinically applied in 14 hospitals in Austria. Although the problem of bone donation needs to be solved in addition to processing technology, with the enhancement of Chinese people’s awareness of donation and the current situation of China’s population base, it is believed that biological bone materials also have huge market potential.

　　Shark screw

　　It is expected that the relevant enterprises in China’s bone nail industry will start from the details, concentrate on research and development, pay attention to innovation, and take advantage of the policy dividend, and small screws can also raise hundreds of millions of markets ~

　　The frame materials of electric wheelchairs are various, and each material has its own unique characteristics, which is suitable for different types of users. First of all, the mainstream frame materials are carbon steel (steel), aluminum alloy, aviation titanium alloy and carbon fiber. Carbon steel has relatively low cost and strong load-bearing capacity, but its disadvantage is that it is bulky and easy to get wet and rust. Aluminum alloy is light and relatively better in corrosion resistance, so many electric wheelchairs on the market use aluminum alloy as the frame material.However, with the development of the industry, 電動輪椅 It will also bring us more and more consumer experiences, so that users can really feel the upgrade and change. https://www.hohomedical.com/collections/light-weight-wheelchair

　　Aviation titanium alloy is a high-end choice, with high strength and corrosion resistance, but the price is correspondingly high, which is usually used in high-end and portable electric wheelchairs.

　　Titanium alloy is a mixture of different elements such as titanium, aluminum, iron and vanadium, which has the characteristics of high strength, corrosion resistance and light weight. Carbon fiber is a composite material made of carbon fiber and resin, which has the characteristics of high stiffness, high strength and light weight. From the perspective of material composition, titanium alloy and carbon fiber have their own advantages, the strength of alloy is higher, but the density of carbon fiber is lower, so the weight is lighter. When it is necessary to reduce weight, it is more suitable to use carbon fiber, which is more durable and stronger than titanium alloy, so the electric wheelchair made of carbon fiber is close to 10 thousand yuan.

　　When choosing the frame material, we should not only consider the material itself, but also pay attention to the design and function of the frame. For example, folding electric wheelchairs bring great convenience to those who are inconvenient to bend over or have disabled hands, so that they no longer have to work hard to fold electric wheelchairs; The conventional electric wheelchair is comprehensive, affordable and stable, suitable for a wider range of users.

모모Views : 906 Update time : 2024-12-17 13:49:56This means that wired pir motion sensor alarm It is the weather vane of the industry and can bring people great self-confidence. https://www.sunlit-tech.com

모모

모모Ensuring security and safety outdoors requires reliable and robust motion detection solutions. At Sunlit-Tech, we specialize in providing high-quality wireless outdoor PIR detectors that offer superior protection and performance. As trusted outdoor PIR detectors manufacturers, we provide cutting-edge technology that ensures your outdoor areas remain secure. Whether for residential, commercial, or industrial use, our outdoor PIR detectors offer unmatched reliability and efficiency. In this article, we몶ll explore the benefits of wireless outdoor PIR detectors, their functionality, and why Sunlit-Tech is the ideal choice for your security needs.

모모

모모outdoor PIR detectors manufacturer.jpg

모모

모모1. What Are Wireless Outdoor PIR Detectors?

모모

모모Wireless outdoor PIR detectors (Passive Infrared detectors) are advanced security devices designed to detect movement over a designated area. These detectors use infrared technology to sense changes in heat, ensuring that any movement of a person or animal is quickly identified. Sunlit-Tech몶s outdoor PIR detectors offer wireless connectivity, eliminating the need for extensive wiring installations. This ensures quick and hassle-free setup while maintaining a clean and aesthetic outdoor environment.

모모

모모2. Key Benefits of Choosing Sunlit-Tech Wireless Outdoor PIR Detectors

모모

모모Reliable and Fast Detection

모모

모모Sunlit-Tech몶s wireless outdoor PIR detectors are known for their exceptional speed and accuracy. The technology embedded in these detectors ensures quick detection of any movement. Whether it몶s a large garden, parking lot, or commercial premises, our outdoor PIR detectors offer reliable protection by promptly identifying potential intrusions.

모모

모모Wireless Convenience and Flexibility

모모

모모The major advantage of our wireless outdoor PIR detectors is their ease of installation and flexibility. No need for complicated wiring setups C these detectors can be installed quickly and efficiently in various locations. Sunlit-Tech몶s outdoor PIR detectors offer adaptability for both temporary and permanent installations, making them ideal for homes, offices, warehouses, and outdoor facilities.

모모

모모Long Battery Life and Durability

모모

모모Sunlit-Tech prioritizes longevity in our wireless outdoor PIR detectors. Built with high-quality materials and energy-efficient technology, these devices offer extended battery life, ensuring long-term functionality. Designed to withstand harsh environmental conditions, our outdoor PIR detectors remain operational in extreme weather, ensuring robust outdoor protection.

모모

모모Seamless Integration with Existing Security Systems

모모

모모Our wireless outdoor PIR detectors are designed to integrate effortlessly with existing security infrastructure, such as cameras, alarms, and smart systems. Sunlit-Tech ensures compatibility with a range of security devices, creating a cohesive system that enhances your overall protection. This integration offers a comprehensive security solution that is both functional and efficient.

　　The expansion screw is composed of a screw and an expansion pipe, the tail of the screw is conical, and the inner diameter of the cone is larger than that of the expansion pipe. When the nut is tightened, the screw moves outward, and the conical part moves through the axial movement of the thread, so that a great positive pressure is formed on the outer peripheral surface of the expansion pipe, and the angle of the cone is very small, so that friction self-locking is formed among the wall, the expansion pipe and the cone, and the fixing effect is achieved.This is due to Forged nut Its value attribute is relatively large, and it is easy to become the backbone of the industry. https://www.chinatianlong.com/

　　The spring washer on the expansion screw is a standard part. Because its openings are staggered and elastic, it is called a spring washer. The function of the spring washer is to use the sharp corner of the staggered mouth to pierce the nut and the flat washer to prevent the nut from loosening.

　　The flat pad is also a standard part, and its function is to evenly distribute the pressure of the nut on the connected parts.

　　Expansion screw specifications:

　　The grades of expansion bolts are: 45, 50, 60, 70, 80,

　　The materials of expansion screws are mainly divided into austenite A1, A2 and A4.

　　Martensite and ferrite C1, C2, C4,

　　Its representation method is, for example, A2-70,

　　”-“indicates bolt material and strength grade before and after, and the following is a complete specification table of expansion bolts.

　　For 45 # steel, alloy steels with high mechanical properties, such as 15Cr, 20Cr, 40Cr, 15MnVB and 30CrMrSi, can be selected for important or special-purpose threaded joints.

　　Choose different expansion screws according to the actual situation of the wall. Generally, there are the following 6〜60, 6〜80, 6〜120 and 6〜150.

　　6〜60: the total length is 60 mm, the sleeve is 45 mm long, the diameter is 8 mm, the wall thickness is 0.7 mm, and the surface is coated with colored zinc; The screw is 60 mm long, 6 mm in diameter, 35 mm in threaded part and 8mm in bottom hammer, and the surface is coated with colored zinc; The nut is octagonal with an outer diameter of 10 mm and a thickness of 5 mm, and the surface is plated with white zinc; The outer diameter of the gasket is 13 mm, the thickness is 1mm, the inner diameter is 6 mm, and the surface is plated with white zinc; The elastic sheet is a ring with an out diameter of 9 mm, an inner diameter of 6 mm and a thickness of 1.6 mm.

　　6〜80: the total length is 80 mm, the sleeve is 65 mm long, the diameter is 8mm, the wall thickness is 0.7 mm, and the surface is coated with colored zinc; Screw length, nut, gasket and elastic sheet are the same as above.

　　6〜120: the total length is 120mm, the sleeve is 105mm long, the diameter is 8mm, the wall thickness is 0.7 mm, and the surface is coated with colored zinc; Screw length, nut, gasket and elastic sheet are the same as above.

　　6〜150: the total length is 150mm, the sleeve is 135mm long, the diameter is 8mm, the wall thickness is 0.7 mm, and the surface is coated with colored zinc; Screw length, nut, gasket and elastic sheet are the same as above.