12.9 level plug screw, hexagonal equal height shoulder bolt, limiting shoulder screw

The center pin on vertical and horizontal pianos, also known as the balance pin, is installed on the middle sleeper of the keyboard frame to fix the keys. Generally, there are 88 keys in the piano, and each key is equipped with a pin hole that matches the center pin. The keys are installed one by one on each center pin through the pin hole. Due to the large number of middle pins and keys, during the production and installation process, in order to ensure the consistency of the flatness of the 88 keys after installation, it is necessary to adjust the middle pins and keys one by one, or add paper rings to the middle fixed part of the middle pins to ensure the consistency of the flatness of the 89 keys. This debugging method is extremely cumbersome and increases the debugging workload, and frequent disassembly of the keys is required when adding paper rings, Due to the limited installation space of the keys, disassembling the keys is troublesome, and multiple installation and disassembly of the keys can easily damage the pin holes on the keys, resulting in a decrease in piano quality.

With the vigorous development of the construction market, fastener type steel pipe scaffolding and template support have been widely used, and a large number of fasteners are used in the fastener type steel pipe scaffolding and template support system. The commonly used fastener structures generally include the fastener body 1, the blade 2, and the rivet 3 used to connect the fastener body and the blade. There is an arc-shaped cavity 4 used to connect the steel pipe between the fastener body and the blade. Figure 5 shows a right angle fastener. However, during the construction process, there are varying degrees of cracks and fractures on the blades of the fasteners, leading to the scrapping of the fasteners, or the scrapping of the fasteners due to poor anchoring of the rivets, resulting in significant waste. Moreover, the damage to the fasteners poses significant safety hazards in construction. However, relying solely on manual repair of damaged fasteners has many technical difficulties, time-consuming and labor-intensive, as well as high operating costs. Therefore, researching and designing an auxiliary device for installing rivets during the repair process of damaged fasteners to reduce worker labor intensity, improve repair efficiency, and reduce operating costs is an urgent technical problem for technical personnel in this field.

The existing spring screws include a screw, a spring connection sleeve, a spring, a fixed connection sleeve, a nut, and a nut sleeve. The screw includes a screw cap, an unthreaded connection section, and a threaded connection section with threads. The connection section is located between the screw cap and the threaded connection section, and a shoulder is set between the connection section and the threaded connection section. The connection section of the screw is sleeved with a spring connection sleeve, a spring, and a fixed connection sleeve, and the spring connection sleeve is tightly attached to the screw cap, The connection sleeve between the spring connection sleeve and the fixed connection sleeve is connected to the spring. The threaded connection section of the screw is connected to a threaded nut, and the nut sleeve is connected to a nut sleeve. The fixed connection sleeve is fixed to the upper mold of the steel mold through bolts, and the nut sleeve is welded to the lower mold of the steel mold. When closing the mold, professional personnel are required to flip the screws from the lower mold to the upper mold or hook them onto the upper mold with their feet and tighten them with wind, which is inconvenient to install, low in work efficiency, and poses safety hazards. The purpose of Yueluo Guangdong Yueluo Hardware Industry Co., Ltd. is to provide a spring screw that is easy to operate. In order to solve the problems existing in the background technology, Guangdong Yueluo Hardware Industry Co., Ltd. adopts the following technical solution: a spring screw, including a screw, an upper pressure spring washer, a spring, a fixed sleeve, a lower pressure spring washer, a base, and a fixed nut. The screw includes a screw cap, a threaded connection section without threads, and a threaded connection section with threads. The connection section is located between the screw cap and the threaded connection section, and a shaft shoulder is set between the connection section and the threaded connection section. The connection section of the screw is sleeved with an upper pressure spring gasket, a spring, a fixed sleeve, a lower pressure spring gasket, and a base, and the threaded connection section is connected with a fixed nut. Connection section and screw

A screw is a tool that utilizes the physical and mathematical principles of the oblique circular rotation and friction of an object to gradually tighten the mechanical components of the object. Screws are a common term for fasteners, commonly used in everyday language. Screws are essential industrial necessities in daily life, such as tiny screws used in cameras, glasses, clocks, electronics, etc; General screws for television, electrical products, musical instruments, furniture, etc; As for engineering, construction, and bridges, large screws and nuts are used; Transportation equipment, airplanes, trams, cars, etc. are used with both large and small screws. Screws bear important tasks in industry, and as long as there is industry on Earth, the function of screws will always be important. The screw has been a common invention in people's production and life for thousands of years, and according to its application field, it is a great invention of humanity

In the past, screws suitable for plastic fastening mostly used self tapping screws, and there were various classifications based on plastic types, such as PT tooth type, Plastic series, Remform tooth type, etc. The structural parameters of these screws are inconsistent with the process technology or require different main molds and wires. Therefore, plastic screws, which are generally applicable to all kinds of plastic types, have a single stamping structure, and the manufacturing process requires low cost and simplicity, especially their special self tapping screws, are important problems that need to be solved urgently at present. The purpose of Guangdong Yueluo Hardware Industry Co., Ltd. is to propose plastic screws to solve the problem of screw tightening that is widely applicable to different plastics. The purpose of Guangdong Yueluo Hardware Industry Co., Ltd. is to achieve plastic screws through the following technologies. The thread of the above-mentioned thread is composed of asymmetric thread teeth with a tooth shape angle of 30, and the connecting bottom surface between the thread teeth is a circular arc surface. The preferred feature of Yueluo is that the clockwise tooth shape angle of the asymmetric thread tooth is greater than the counterclockwise tooth shape angle, and the sum of the bidirectional tooth shape angles is 30. Yue Luo's preferred asymmetric threaded teeth have a forward tooth profile angle of 20 degrees and a reverse tooth profile angle of 10 degrees. The application of plastic threads by Guangdong Yueluo Hardware Industry Co., Ltd. has reduced the radial pressure and installation torque during thread installation and reduced the damage to plastic holes through the improvement of special thread structures. In addition, the anti loosening force of the screws is also applied to prevent assembly loosening. In addition, the design of the bottom surface of the circular arc threaded peak to peak connection optimizes the material flow of the installation object, playing a role in the integrity of the installation connection. In order to better understand and master Guangdong Yueluo Hardware Industry Co., Ltd