With the development of human society, economy and science and technology, zippers have developed from initial metal materials to non-metallic materials, single varieties and single functions to multi-variety and multi-specification comprehensive functions, from simple structures to today's exquisite and beautiful , colorful and has gone through a long process of evolution. Its performance, structure, and materials are changing with each passing day, and it has a wide range of uses. It has penetrated into various fields such as aerospace, aviation, military, medical, and civilian use. The small zipper plays an increasingly important role in people's lives and increasingly shows its importance. sex and vitality. The zipper, as one of the ten most practical inventions for mankind in this century, has been recorded in the annals of history.
History of Invention
Zippers are also called zippers. It is one of the top ten inventions in modern times that has facilitated people's lives.
The zipper was invented a century ago. At that time, in some places in central Europe, people tried to replace buttons and bows with belts, hooks and loops, so they began to experiment with developing zippers. Zippers were first used in military uniforms. During World War I, the U.S. Army ordered a large number of zippers for the first time to make clothing for soldiers. However, the promotion of zippers in the private sector was relatively late. It was not until 1930 that it was accepted by women as a replacement for buttons on clothing.
The zipper received its current name in 1926. According to reports, a novelist named Franco said at a business luncheon to promote a zipper sample: "Pull it, and it opens! Pull it again, and it closes!" Very concisely. Describes the characteristics of zippers. This is where the word zipper comes from.
The prototype of the zipper originally came from the boots worn by people. In the mid-19th century, high boots were very popular and were particularly suitable for walking on muddy or horse excrement roads. However, the disadvantage was that the high boots had more than 20 hook-type buttons, making them extremely time-consuming to put on and take off. This shortcoming troubled the inventor and cost the sponsor a lot of money and patience. In order to avoid the trouble of putting on and taking off their boots, people even endured wearing their boots all day without taking them off. Finally, in 1851, American Elias Howe applied for a patent for a zipper-like design, but it was not commercialized and was even forgotten for half a century.
In 1893 (some say 1883), an American engineer (Kuwaiti) named Judson developed a "sliding tightening device" and obtained a patent. This was the first prototype of a zipper. The emergence of this device had an impact on the button hooks used on high boots. However, this invention did not become popular quickly. The main reason was that the quality of this early locking device was not up to standard and it was easy to loosen at inappropriate times and places, causing embarrassment.
In 1913, the Swede Sandback improved this crude locking device and turned it into a reliable commodity. The method he used was to attach metal locking teeth to a flexible shaft. This zipper works like this: Each tooth is a small hook that mates with an eyelet underneath a small tooth on the next and opposite strap. This type of zipper is strong and can only be opened when the slider slides so that the teeth open.
It was not until the 1890s that a turnaround occurred. Whitcomb L. Judson, a mechanical engineer from Chicago, came up with the idea of ??using a sliding device (slider– device) to fit and separate two rows of buttons (this principle is very similar to that of a zipper, but the term zipper did not appear until about 30 years later). Judison's invention was fortunate to receive financial support from Pennsylvania lawyer Lewis Walker. Walker was highly interested in Judison's new design.
During World War I, the U.S. economy was in a slump. Steel cost five cents per pound, and workers' wages were six dollars a week. The company reduced its layoffs, leaving only Senbeck and others. A person, Sembeck is both a manager and an engineer. The company's economy encountered unprecedented difficulties. In order to repay thousands of dollars in arrears to the Roblin Company that provided the steel wire, Senbeck had to repair a machine to produce paper clips to make money.
Fortunately, sponsors kept coming, and the playwright's father, James O'Neill, who was touring with his play "The Count of Monte Cristo," was extremely enthusiastic about Sembek's Pratton zippers. interested.
Although there was a turnaround in his career, Sembek suffered an unprecedented personal blow. His wife died in childbirth. While Sembek was sad, he devoted himself even more to improving zippers. He applied for a patent again in 1913, and the patent license was approved in 1917 (Patent No. 1219881). Walker calls the patent a "hidden hook" and is optimistic about the prospects. Walker renamed the company "Hookless Fastener Company" and moved the factory to Meadville.
Senbeck further improved the hookless button. The shape of the teeth was changed to a spoon shape, with a convex top and a concave end. The left and right "teeth-shaped parts" can be fitted with one slide of the sliding device. The slide back was separated, called the "Hookless No. 2," and a machine was devised to make the toothed portion. In 1913, he officially announced that this technology had been broken through. "American Science" once used Sembeck's patent as a cover story.
Six months later, Senbeck was ready to mass-produce this button, and hookless No. 2 was ready to go on the market.
Walker's second son also spent eight years working on improving hookless buttons. Josephine Calhoun of Florida also applied for a patent for a similar safety zipper in 1907. In the same year, Frank Canfielt of Colorado also applied for a patent. Inventors dedicated to research in this area are not only found in the United States. Among them, the ones closest to Sembeck's final product are those patented in 1912 by Zurich's Katharina Kuhn-Moos and Henri Forster. However, Neither has become a commercial product like the hookless No. 2.
Market demand determines the success or failure of a product. There were not many orders for Hookless No. 2 at first. Mcreery department store in Pittsburgh believes that hookless No. 2 is very suitable for use on skirts and suits, and requires manufacturers to adopt hookless No. 2. However, there are not many imitators and they do not dare to take the risk of using new products. In order to win customers, Senbeck constantly improves the performance of zippers to meet needs.
Medville's factory has become increasingly sophisticated in its manufacturing technology. It manufactures 1,630 hookless No. 2s every day without any defective products. As a result, orders are increasing day by day. The First World War also brought new opportunities for new products. Soldiers' money belts increased the demand for hookless No. 2; the use of hookless No. 2 in Air Force flight suits not only saved materials, but also had better windproof effects. ;The Navy's life jackets also use hookless No. 2. The government then allocated special metal materials for production.
Although Hookless No. 2 has proven to be useful, it is still not popular because of its high price. Senbeck understands this and is committed to reducing production costs and improving manufacturing efficiency. He invented the S-L machine to reduce unnecessary waste of materials during the production process, requiring only 41℅ of the original raw materials. After reducing production costs, the first product applied was the Locktite tobacco bag. The sales were quite successful. By the end of 1921, the tobacco company required an unprecedented number of hookless No. 2s every week. To accommodate the high demand, the Hookless Button Company built a new factory.
In 1921, the B.F. Goodrich Company of Ohio ordered a small amount of products from the Hookless Button Company to be used in the rubber galoshes they produced. After trying it out, we found that the effect was good, so we ordered a large number of them and informed the Hookless Button Company of the shortcomings we discovered. After improvement, the company launched the Mystery Boot, which is characterized by being able to put it on or take off with just a pull.
The marketing staff was not satisfied with the name of Wonder Boots and wanted to find a name that could better show its characteristics. The manager was inspired and thought of the onomatopoeic word "Zip" - the sound of an object moving quickly. The Wonder Boots were renamed Zipper Boots (see Figure 2). The year was 1923. Later, "Zipper" - "zipper" became the general name for all similar hookless button products. Unfortunately, Judithson passed away in 1909, never hearing the term "zipper" before his death, nor did he see his invention become popular around the world.
That winter, Haofu sold nearly half a million pairs of zipper boots. In the mid-1920s, it bought at least a million zippers a year from Hookless Button Company. Hookless Button Company felt that The word "hookless" has a negative association, and the word "zipper" was coined by a wealthy company. Therefore, the term "Talon" was thought up, and the company was renamed Talon in 1937.
Before 1930, the Hookless Button Company sold 20 million "Eagle Claws" each year, with applications ranging from pen cases to motorboat hoods. But the ready-made garment industry is still waiting and not using it. By the mid-1930s, fashion designer Elsa Schiaparelli was using "eagle claws" extensively for the first time. The New Yorker described the 1935 spring fashion show as "full of zippers." . Since then, the garment industry has gradually adopted zippers.
With the spread of the product, zipper manufacturing technology has gradually spread around the world. European countries such as Switzerland and Germany, and Asian countries such as Japan and China have successively begun to establish zipper production factories.
In 1917, zippers were introduced to Japan. At that time, due to their scarcity, zippers could only be used as accessories for dignitaries to show off their status. In 1927, in the early Showa era of Japan, Onomichi people in Hiroshima Prefecture began to manufacture zippers and began selling them under the trademark "Clip Brand". At that time, zippers were known for their durability, so "clamp" became synonymous with zippers. To this day, the Japanese still call "zipper" "clamp".
In 1932, Japan began to mass-produce zippers by hand. As advanced machines such as eccentric manual punches were continuously developed at the time, zippers could be mass-produced, prices gradually dropped, and the clothing and luggage industries began to use zippers, making the industry outlook very active.
In 1934, zipper products from Shanghai, Hong Kong and the United States began to be exported in batches. The "Three S Chamber of Commerce", the predecessor of Japan Yoshida Industry Co., Ltd., was founded on January 1 of this year.
After 1937, zippers were sold in large quantities in North America, Central and South America. Zippers finally appeared as an emerging industry, and similarly, zippers also became an important role in Japanese industry. However, the Pacific War broke out in 1941, and Japan eventually became a defeated country. The war brought a devastating blow to Japan's domestic industry, including the zipper industry. At that time, except for some military zipper manufacturers who stayed, almost all other factories were forced to change jobs or Waste industry.
After the war in 1946, due to the influence of the U.S. military stationed in Japan at that time, the demand for zippers increased rapidly. However, the huge trauma caused by the war made the Japanese zipper industry unable to cope with demand in the short term. "Japanese-style manufacturing method", the shortcomings of handicraft manufacturing are fully exposed. At that time, it created a bad image of "zippers easily broken" made in Japan.
In 1950, Japan's "Yoshida Industry Co., Ltd." imported automatic chain element machines, taking the first step into mechanized production. Subsequently, the company invented the automatic punching machine for sliders and successfully developed it. It not only solved the shortcomings of past manufacturing, but also reformed the manufacturing process to the production process, thereby driving the progress of the entire zipper industry in Japan. (Japan Yoshida Co., Ltd., product name YKK, has factories in six locations in the country, including Akichi, Kurobe, Koshiko, Tohoku, Shikoku, and Kyushu, and has established factories in more than 40 countries and regions overseas) In 1951, Japan itself The 30 chain element manufacturing machines manufactured were put into use, finally completing the modern factory equipment that is unrivaled in the industry.
Almost at the same time as the Japanese zipper industry developed, zippers in some European countries, such as Switzerland and Germany, were also developing.
In the 1930s, the Swiss company Optilon was established and headquartered in Zug, Switzerland. For decades, the company has taken "comfort" and "quality" as the first elements and continuously improved its design. Through technical cooperation with more than 30 foreign companies, new varieties of zippers have continued to appear. It has established companies and companies all over the world. The factory has become a world-class zipper company as famous as the American Tailong Zipper Company and the Japanese Yoshida Co., Ltd.
In 1953, Germany introduced the first zipper made of plastic, pioneering non-metal zippers.
my country's zipper production was introduced to Shanghai from Japan in 1930. At that time, Wang He established my country's first zipper factory on Houjia Road in Shanghai. Later, Wu Xiangxin opened another zipper factory, and in 1933 he founded the Shanghai Samsung (namely Huaguang) Zipper Factory.
In 1949, there were more than 20 small and medium-sized zipper companies in my country, employing about 1,000 people. Mainly relying on manual operation, the equipment is rudimentary.
In 1958, Shanghai Samsung Zipper Factory introduced an automatic rice arranging machine produced in Germany and carried out technical reforms, increasing the speed of the automatic rice arranging machine from 1440 rpm to 3000 rpm, which is equivalent to a manual 230 rpm. times; the production of sliders has been reformed from single-head punching to twelve-pass molding at one time, improving production efficiency by more than 50 times; the subsequent processes include flattening, brushing, tape washing, waxing, tape doubling, shuttleless looms and other efficient special equipment The reform was successful; new processes and technologies such as aluminum-magnesium alloy liquid drawing and cemented carbide sintering into integral molds were promoted, realizing the first technological revolution in my country's zipper industry.
In 1958, the invisible zipper (CONCEAL) went on sale.
In 1959, The Grand (L type) went on sale.
In 1961, the Delrin resin zipper injection molding machine was launched, and Delrin resin zippers began to be sold.
In 1963, EFJON double-bone zipper went on sale.
In 1971, BEULON zippers with knitted fabrics were put on sale.
In 1974, Beijing introduced nylon zipper (horizontal) production equipment from Switzerland; Tianjin introduced eight polyester zipper production equipment produced in France; soon domestic companies such as Shanghai, Zhejiang, Hubei, Guangdong, Other places have successively introduced non-metallic zipper equipment from Germany, Japan, Taiwan and other countries and regions, and non-metallic zipper equipment has begun to develop in our country.
In 1978, zippers for fishing nets were sold.
In 1979, VISLON, a resin zipper with wings, went on sale.
In 1985, watertight and airtight zippers began to be sold.
In 1988, JOYLONR track zipper went on sale.
In 1989, ion-plated zippers were put on sale.
In 1991, the injection molded QUICKLON zipper went on sale.
In 1992, EVER BRIGHT, VISLON thermal transfer zippers, and injection molding (molded zippers) began to be sold.
In 1993, Q meshe (QUICKLON), Q mate (paired QUICKLON), and Q touch (curtain track QUICKLON) began to be sold.
In 1994, wide-width die casting QUICKLON (continuous injection molding) was launched in Dali. Start selling. From August 1, "Japan Yoshida Co., Ltd." will be renamed "YKK" company.
Since 1980, especially after 1995, my country's zipper production has developed at an unprecedented speed. A large number of emerging private zipper companies have emerged and their scale has continued to expand. Zipper products are constantly increasing. At present, the three major types of zippers in the world can basically be produced in various varieties and specifications. In 1999, my country's zipper production achieved its first historic leap, with output exceeding 10 billion meters, becoming the world's largest zipper producer.
Display zipper
Judithson demonstrated his new invention at the World's Columbian Exposition in Chicago in 1893, making it on shoes and wearing them directly on his feet (patent application Dated August 29, 1893, Patent No. 504038). Walker appreciated this invention very much, and the two formed a partnership in 1894, the Universal Fastener Company, and applied for a patent again in 1896. But the product was a bit bulky and unpopular with the manufacturer. Later, this product was used in mail bags, but only 20 bags were in use before the end of 1897. Walker applied this design to military shoes and earned the nickname "Colonel Walker".
Improved design
Judison continues to improve the design of its products to meet the needs of corsets. He spent all his efforts to continuously introduce new inventions, but each progress brought more new problems and cost a lot of money. Partner Walker once described the difficulty of invention, saying that he discovered more problems than he solved during the process.
In 1901 Judison applied for a patent for a machine that could connect a row of zipper teeth. But the machine was too complicated to use, so the global sliding button company was depressed for a while. Later, the Fastener Manufacturing and Machine Company was established to research and develop machines for sewing zippers, eliminating the inconvenience of manual sewing. In 1904, the company was renamed the Automatic Hook and Eye Company, and the product was named C-curity. This took advantage of the fact that the convex zipper would not loosen easily, but zippers still often occurred. If it pops open or gets stuck, the entire zipper has to be removed from the garment.
The shortcomings of Judson's design were later solved by Otto Frederick Gideon Sundback, a Swede born in 1880. Senbeck was interested in mechanics since he was a child. He studied in Germany and returned to serve in the country after receiving a degree in electrical engineering in 1903. Later, he immigrated to the United States. I just started working at Siemens in Pittsburgh. Because the work location was very close to Pennsylvania, where the shareholders of the Automatic Hook Button Company, which produced safety zippers, lived. The geographical relationship and the disagreement between Sembeck and his boss at Siemens made him switch to Automatic Hook. The button company's factory is located in Hoboken, New Jersey.
Since 1908, Senbeck began to study the improvement of zippers. He thought hard day and night. He tried to find a way to make the toothed part of the zipper close to prevent it from bursting open, and renamed the safety zipper to the Pula buckle ( Plako) zipper (the patent was only applied for in 1913, and the patent number is 1060378. This design is considered an important milestone in the advent of the zipper). However, Senbeck's dream did not come true. The new product still had shortcomings, and many consumers wrote to complain.
Edit the technical specifications of this paragraph
3# invisible zipper
Combined width 4.15 0.03 Single width 2.65±0.03 Thickness 2.10±0.05mm
Electroplating slider: mouth width 4.4mm, mouth height 1.9mm
Painted slider: mouth width 4.35mm, mouth height 1.85mm
Ordinary belt is suitable for thick fabrics; lace belt is suitable for thin fabrics .
Ordinary top stop: Advantages: High output (adjustable speed); Disadvantages: Sometimes the top stop cannot be pulled to the root
U-shaped top stop: Advantages: The top stop can be pulled to the root , suitable for clothing that requires pulling to the roots; Disadvantages: low output, 4,000 pieces/8 hours.
Factors that easily lead to defective products of the 3# invisible zipper: the large blade is bent; the joint of the microphone teeth is slightly scratched when the size is determined, causing the lower stop to be welded not in place, and the upper stop also exposes the microphone teeth, so that the upper stop is not welded in place. The stopper is easy to fall off; the leader has different lengths; there is no insurance after the slider is painted.
3# nylon zipper
Combined width 4.15±0.05 Single width 2.65±0.03 Thickness 2.00±0.05mm
Slider opening height: 2.05-2.15 Slider Mouth width: 4.2-4.25
Closing: When setting the size, there is no need to distinguish between high and low microphones, so sometimes the head can be turned to open; when the stop is laid, the weft density of the fabric edge is loose and prone to spinning, which affects the appearance and is the worst. Fortunately, the pattern of the tape within the width of the bottom stop adopts an up-and-down weaving method, so that the bottom stop penetrates the tape and is not easy to spin; the top stop position must be ensured to be flush, with the front leader 2.2mm, the rear leader 1.8mm, and the front and rear code leaders for injection molding. To ensure 4.0mm.
Opening and tailing: It is difficult to select teeth in a fixed size. Because the tooth spacing is relatively small (1.2mm), it is best to use a fixed code installation. The right insert is high, the left is high and the right is low. Manual trimming is required, and half a bead of ultrasound is required. Press the microphone to the root, the shins on both sides are evenly distributed, and the upper thread is continuous. The length of the punched cloth leg is about 8mm. When pressing the square latch, the pulling speed should not be too fast. The force on both sides is even and the pull is in place. The pressing mechanism must be slow to work. , so that the mold is not easily damaged, the pressure changes from high pressure to low pressure, and the mold is closed slowly, and then the high-pressure action pressure changes from low pressure to high pressure, and high-pressure mold locking is performed. The difference between the two induction switches is about 20mm, because the thickness of 3# nylon is thin , so the difference in action of the sensor switch is small, and the requirements for adjusting the position of the sensor switch are relatively high. The specific adjustment method is: when the zipper is in neutral, the sensor switch light turns on, go to the high part of the zipper microphone, the sensor lever moves, and the sensor switch light goes out. Press the fishing needle down, hook the hole in the patch and the microphone teeth into place and push it down.
Factors that easily lead to defective products of #3 nylon zippers: Due to the coding, the upper thread is easy to break when the size is determined, and half of the microphone is not crushed by the ultrasonic wave, causing the pressure to open and pull the tail in place.
Note: 3# nylon zipper needs to be accompanied by the tail slider. If the code is normal, the top stop can be injection molded.
5# nylon zipper
Pull Head and mouth height: 2.9-3.0 Mouth width: 6.5-6.6 Combined width: 6.45±0.05 Single width: 4.15±0.05 Thickness: 2.70±0.05
Ordinary open tail: fixed-size tooth selection should be installed according to different codes Adjust at any time (due to changes in tooth spacing), ensure that the left is higher when inserted on the right, and vice versa when inserted on the left. The ultrasonic half microphone is pressed to the root. The position of the tape should be flush, ensuring that the pinholes of the latch square are flushed to the bottom. Punch the cloth The length of the foot is about 9.5mm. Make sure that the latch square is installed at the root, and the latch punch needle penetrates the center. The shin side of the block must be clamped firmly, and the punch needle penetrates the center.
When repairing the folding mold, you must pay attention to the inclination of the lower mold, that is, when inserting the right side, the left side is higher and the right side is lower, and vice versa. A strong test must be carried out to ensure that it is qualified before production.
Factors that are prone to defective products: due to the opening of the cloth legs that are too short or too long, resulting in insufficient strength respectively, the latch square cannot be installed at the root, causing the square head to be crooked, difficult to match, and the strength does not meet the standard. value, the reason is that the punching hole is too far away from the outer side of the tibia, and the punching hole is too deep, causing the tibia to break.
Injection molding opening and closing: Same as above for fixed size and ultrasonic sound. You need to change the mold to open it. (Note: When changing the mold, pay attention to the starting position, because the mold stroke is different, otherwise the mold will be easily damaged). Specific adjustments You can put a piece of paper into the mold, turn the wheel on the hand, and the paper should be cut just right. The length of the punching foot is 9.5mm. For the square latch, please refer to the 3# nylon open-tail press.
5# nylon double-open tail
The fixed-inch ultrasonic zipper is the same as the 5# nylon zipper. The perforated cloth leg is about 13cm long. Make sure that the square latch is installed to the root and the four pinholes are centered. For penetration, the block must fall into place, otherwise defective products are likely to appear. The separate parts and sliders must be matched. If there are special sliders, it is recommended to test whether they match before mass production. When punching, the needle is off-center or the separate parts are broken. The solution is to stack the punching needle faces in different directions.
3# resin zipper
The slider opening height is 2.6-2.7MM, the opening width is 4.75-4.85, the combined width is 4.55± 0.05, the thickness is 2.4±0.05
Closed tail : When pressing up and down, the temperature, injection delay, and holding time must be adjusted appropriately. If the size of the closed-tail zipper is about 15CM and there are a certain number, you can use one mold with two strips to stop the zipper. Similarly, if There are suitable sizes and quantities, and they can also be molded one by one.
Opening and tailing: When determining the size, make sure to take the lead? FONT face="Times New Roman"gt; 4.5cm, (17 microphone teeth), the pattern of the ultrasonic tape is clear, even on the left and right, and the position is away from the microphone The teeth are about 1.5mm, ensuring that the punching crochet hook can be hooked firmly and punched through.
Press adjustment: high pressure should not exceed 100kg/cm2, injection pressure should be 40kg/cm2, holding pressure 30kg/cm2, low pressure should be less than 10kg/cm2, high pressure and holding pressure cooling time should be more than 0.1 seconds, specific It should be adjusted according to the actual product (zipper model).
Factors that are prone to defective products: exposed shins (the reason is whether the upper and lower mold positioning pins are broken and whether they are appropriate), the pins fall off (whether the injection pressure is appropriate, whether the holding pressure and cooling time are sufficient), the seams of the square fabric are small (The pressed zipper needs to cool before putting on the slider)
5# resin zipper
The slider opening is 3.2-3.3MM high, 6.05-6.15 wide, combined width 5.75± 0.05 Thickness 2.95±0.05
Closing: please refer to the 3# resin closing
Opening: fixed size to ensure the head is 5cm (14 mic teeth), fine teeth are 5.1cm (21 Microphone teeth), the pattern of the ultrasonic tape is clear and even on the left and right, and the position is about 2mm away from the microphone teeth, ensuring that the punching crochet hook is firm and the hole is punched through
Double open tail: the position of the ultrasonic tape is 2.5mm away from the microphone teeth The same goes for everything else. If the resin zipper tape is pressed too deeply and then the tail is opened by pressing, the root of the tape will easily break.
8# resin zipper
Slider opening height 4.15-4.25MM, opening width 8-8.1, combined width 7.4±0.05, thickness 3.9±0.05
Opening tail : Fixed-inch mic head 5.9-5.95 (14 mic teeth), fine-thread mic head 5.55-5.6cm (23 mic teeth)
10# resin zipper
Slider opening Height 4.15-4.25MM, mouth width 8.9-9, combination width 8.2±0.05, thickness 3.95±0.05
Opening and tail: fixed-inch row microphone head 6.05-6.1 (12 microphone teeth), the pressure should be 5 # should be adjusted higher and the time longer to ensure that the square pins are full and smooth.
3# metal zipper
Slider opening height 2.1-2.2MM, opening width 4.55-4.65, combined width 4.45± 0.05, thickness 1.95±0.05
Closed tail : After determining the size of the microphone teeth, the damaged ones must be removed, the top and bottom should be flush, and the band should be tightly wrapped
Opening and tailing: The patch is about 1.8mm away from the microphone teeth to ensure that the punched crochet hook can be hooked Make sure the punched cloth leg is about 8mm long, make sure the latch square is installed to the root, and the pin hole must be punched into the tape and centered.
5# metal zipper
Slider opening height 2.7-2.8MM, opening width 6.0-6.05, combined width 5.90±0.05, thickness 2.6±0.05
Closed tail : Refer to the 3# metal zipper
Opening tail: After determining the size, remove the bad microphone. The patch is about 1.8mm away from the microphone teeth to ensure that the punched crochet hook can be hooked firmly. The length of the punched cloth foot is about 8.5mm. Make sure the latch square is installed to the root, and the pin hole should be punched into the tape and centered.