What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
At present, the main four kinds of anti-shedding nuts are still prone to falling off. Friction and anti-shedding are in the case of shock, vibration and variable load. At the beginning, the nut will decrease in preload due to relaxation. As the number of vibrations increases, the loss of preload will increase. The force increases slowly, eventually causing the nut to loosen and the threaded connection to fail. The mechanical nut is prevented from falling off by adding a stopper, which makes it inconvenient to disassemble. The riveting and punching prevention is to prevent the separation by welding, bonding, etc. This method can only be disassembled by destroying the bolt pair.
T-bolt is a common fastener, which is mostly used where there is a T-slot on the workbench or where the connection can only be made from the side to be connected. However, it has the following problems in the actual production and processing process. 1. The T-bolt manufactured according to the current GB37-88 is used in conjunction with the T-slot on the worktable, which is easy to damage the T-slot on the worktable. 2. According to the observation and investigation, it is found that 90% of the damage to the T-bolt manufactured by GB37-88 is thread damage during use, and the T-shaped part is rarely damaged, resulting in a waste of raw materials. SUMMARY OF THE INVENTION The purpose of the present invention is to solve the problem that the current composite T-bolt is easy to damage other equipment and cause waste of raw materials in the actual use process, and to provide a simple structure, easy to use, safe and reliable, and not easy to damage other equipment. , thereby saving raw materials and other advantages of composite T-bolts. In order to achieve the above purpose, the present invention adopts the following technical scheme: a composite T-bolt, which includes a bolt, and one end of the bolt is connected with the T-shaped block cockroach. The T-shaped block is provided with a tapered hole, and the connection between the bolt and the T-shaped block is a cone, which is matched with the tapered hole. The utility model combines the two parts of the T-shaped block and the threaded bolt through the T-shaped block and the taper hole and the cone on the bolt to automatically lock the two parts before use. When the threaded part of the bolt is damaged, only the threaded bolt needs to be replaced. That's it. Compared with the domestic T-shaped bolts currently produced in the manufacturing process, the utility model solves the problems of complicated manufacturing processes and waste of raw materials. It is well known that the manufacture of T-bolts requires processing such as forging, turning, milling, and heat treatment. Since the composite T-bolt is used in combination with the T-block and the bolt, and the T-block is rarely damaged, after purchasing or manufacturing the T-block once, you only need to purchase or manufacture the bolt in the future. Compared with the T-bolts currently produced in China, the composite T-bolts can better protect the T-slots on the working surface. Because the T-bolt currently produced in China will rotate a certain angle around the axis of the T-bolt when fixing the object, the T-bolt will rotate at a certain angle, thereby reducing the contact between the T-bolt T-shaped surface and the T-slot stress surface of the working face. surface, causing stress concentration on this surface. The composite T-bolt avoids the above problems due to the increase of the guide surface, thereby protecting the T-slot. The beneficial effects of the utility model are: 1. Saving raw materials. 2. Reduce processing costs. 3. Simplify the technological process. 4. Protect the T-slot.
1. Standards for fastener product dimensions: specify the content of the basic dimensions of the product; threaded products also include the basic dimensions of the thread, thread end, shoulder distance, undercut and chamfer, and the end of externally threaded parts size, etc. 2. Standards for technical conditions of fastener products. It mainly includes product tolerances, mechanical properties, surface defects, surface treatment, product testing standards and corresponding specific provisions. 3. Standards for screw product acceptance inspection, marking and packaging: specify the qualified quality level and sampling plan of random inspection items during product acceptance inspection, as well as product marking methods and packaging requirements. 4. Marking method standards for standard parts, fasteners, screws and screws: specify the content of the complete marking method and simplified marking method of the product. 5. Standards for other aspects of fasteners: such as standards for fastener terminology, standards for fastener product weight, etc.
A hand screw is a screw with a plastic head, and the user fixes the hand screw by turning the plastic head by hand. At present, a hand screw is disclosed in the market publication number CN202203253U, which includes a plastic head and a screw rod, the plastic head and the screw rod are connected together, and the height of the plastic head is higher than that of an ordinary screw, and the height is 13 cm. The screw of the hand screw is fixed in the plastic head by glue. After a period of use, the aging of the glue leads to the loosening of the screw and the plastic head. When the plastic head is stressed, the screw rod comes out of the plastic head, which affects the normal use of the hand screw.
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