What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
screw is a tool that uses the physical and mathematical principles of the circular rotation and rotation of the oblique surface of an object to gradually fasten the mechanism of the utensil. A screw is a common term for fasteners, an everyday colloquial language. Screws are indispensable industrial necessities in daily life: tiny screws used in cameras, glasses, clocks, electronics, etc.; general screws in televisions, electrical products, musical instruments, furniture, etc.; as for engineering, construction, and bridges, large screws are used. Screws and nuts; transportation equipment, airplanes, trams, automobiles, etc. are used together with large and small screws. Screws have important tasks in industry. As long as there is industry on earth, the function of screws will always be important. The screw is a common invention in people's production and life for thousands of years. According to the application field, it is a great invention of human beings. At present, the head of the screw on the market is generally punched with a cross groove or a word groove, which is used for tightening or Remove the screw, but the cross slot or the slot is easy to deform after a long time, it is difficult to disassemble it with tools, and sometimes the tool of the corresponding size cannot be found and the disassembly cannot be carried out, and the disassembly is relatively inconvenient.
Contents of the utility model Guangdong Yueluo Hardware Industry Co., Ltd. is to solve the problem of needing one hand to hold the screw when screwing the screw at present, and to provide a screw fixture that can screw the screw without holding the screw by hand. Guangdong Yueluo Hardware Industry Co., Ltd. adopts the following technical solutions. Guangdong Yueluo Hardware Industry Co., Ltd. includes a clamp sleeve, and the middle of the clamp sleeve is a through hole. The outer end of the pivot pin is in contact with the spring. The beneficial effect of Guangdong Yueluo Hardware Industry Co., Ltd. is because Guangdong Yueluo Hardware Industry Co., Ltd. is provided with a rotating pin on the shaft of the fixture sleeve that can contact the screw, and the outer end of the rotating pin is in contact with the spring, so that the screw It is easy to fix in the through hole of the fixture cover, and the screwdriver is also in the through hole of the fixture cover, which ensures the alignment of the screw and the screwdriver, so it is avoided to hold the screw by hand, and the screw is quickly screwed to the object. in vivo.
Slotted Round Head Wood Screws GB 99-86 Slotted Countersunk Head Wood Screws GB 100-86 Slotted Half Countersunk Head Wood Screws GB 101-86 Hexagon Head Wood Screws GB 102-86 Cross Recessed Round Head Wood Screws GB 950-86 Cross Slotted countersunk head wood screws GB 951-86 Cross recessed countersunk head wood screws GB 952-86
According to the development and evolution process of self-tapping screws, we believe that the main types of self-tapping screws are as follows: 1. Common self-tapping screw threads are self-tapping threads, also known as wide thread. The surface is mostly electroplated. 2. Self-cutting and self-tapping screws are called scraping ends of self-tapping screws in my country's standard. The threads are self-tapping threads or machine threads, and the cross grooves are also H type. There are several types of self-cutting self-tapping screws: cross recessed pan head self-cutting self-tapping screws, cross recessed countersunk head self-cutting self-tapping screws. Cross recessed countersunk head self-cutting self-tapping screws, hexagon head self-cutting self-tapping screws. 3. Self-extrusion and self-tapping screws (self-tapping locking screws) The threads of self-extrusion and self-tapping screws are generally machine threads, and self-tapping threads are rarely used. In the wrenching method, in order to ensure the use of high-speed automatic assembly wrenches, slotting is generally not recommended. The cross section of the screw of the self-extrusion self-tapping screw is triangular. So it is also called triangular thread screw. 4. Self-drilling and self-tapping screws (self-drilling screws) The threads of self-drilling and self-tapping screws are self-tapping threads according to Chinese, German and international standards. In the American ASME and SAE standards, the BSD self-drilling self-tapping screws are self-tapping threads, and the CSD self-drilling self-tapping screws are machine threads. Self-drilling self-tapping screws are not recommended for slotted and normal hex head. 5. Metal driving screws (metal tapping screws) The metal driving screws have multiple threads and special threads with a certain helix angle. Only the American standard has metal drive screws, and there are no Chinese and German standards. 6. Wallboard self-tapping screws (dry wall screws) Wallboard white tapping screws are special threads with horn head, cross groove (H type) and 60° profile angle, and the surface is mostly phosphate treatment (phosphating). 7. The cross groove of the fiberboard nail is Z-shaped, and the surface treatment is mostly electroplating. There are several types of fiberboard nails: countersunk head, double countersunk head fiberboard nails, pan head, pan head flange (with pad) fiberboard nails, semi-countersunk head, semi-countersunk head flange (with cushion) fiberboard nails. 8. Combination self-tapping screws Ordinary self-tapping screws, self-cutting self-tapping screws, self-drilling self-tapping screws, etc., and flat washers, elastic washers (including spring washers, elastic locking washers, etc.). 9. Others Self-tapping screw types High and low thread double lead self-tapping screws, coarse and fine thread (different pitch) thread self-tapping screws, threads coated with sealing material (fall resistance) self-tapping screws, various composite groove self-tapping screws, Other special self-tapping screws, etc. In short, there are many types of self-tapping screws. With the development of production, the advancement of technology, new materials, new structures, and new thread forms, new self-tapping screw products will continue to appear.
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