What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Existing wood screws are composed of a threaded portion with a tapered angle and arranged along a tapered stem and a screw head. The head of the screw can be a countersunk head, hemispherical, or other shapes, and the head of the screw has a groove that fits with the tool, a word groove, and a concave cross groove. The taper angle of existing wood screws is either 45 degrees or 60 degrees, and the front end of the taper angle is a pointed point formed by a rotating thread. The existing wood screws have the following three deficiencies in use. Because the taper angle is 45 degrees or 60 degrees, and the thread angle is 64 degrees, the resistance when entering the material is relatively large, so the existing wood screws are manually screwed. It is difficult to screw in, especially when it is used for hardwood materials, and it often happens that the groove of the screw head is screwed out; A large lateral moment will be formed when the screw is screwed, which is prone to the problem of deviation from the position; in addition, because the existing screw is tapered, it will be subjected to both radial force and axial force when entering the material, and its stress state It is more complicated, so it is easy to cause the cracked wood material to burst, and even cause the material to have longitudinal cracks and be unusable.
Countersunk head, half countersunk head, 1200 countersunk head, half countersunk head rivets are mainly used for riveting occasions where the surface needs to be smooth and the load is not large. Flat head rivets are used for riveting occasions subject to general loads. Flat head and flat head rivets are mainly used for riveting of metal sheets or non-metallic materials such as leather, canvas and wood. Large flat head rivets are mainly used for riveting of non-metallic materials. Semi-hollow rivets are mainly used for riveting occasions with little load. Headless rivets are mainly used for riveting of non-metallic materials. Hollow rivets are light in weight and weak in head, and are used for riveting of non-metallic materials with little load. Tubular rivets are used for unloaded riveting of non-metallic materials. Nameplate rivets are mainly used for riveting nameplates on machines and equipment.
screw is a common connecting piece, a tool that uses the physical and mathematical principles of the circular rotation and friction of an object to fasten the parts of the object step by step. 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. A traditional screw is generally set as a screw head at one end and a screw rod at the other end, which cooperates with an external nut to fasten the connector between the screw head and the nut. However, such as some home appliance modules, chassis and other electrical appliances, the modules and boxes fixed by traditional screws often fasten many parts together by screws. During maintenance, it is necessary to disassemble all parts of the maintenance part, which is very troublesome. Therefore, a new type of screw structure that can be connected at both ends and can realize layered installation is required. During maintenance, only the connecting layer of the maintenance part needs to be disassembled, and neither the exterior nor the interior needs to be disassembled.
When the rivet is riveted, it is often necessary to locate and fix the rivet. However, the common rivet positioning mechanism at present often has no way to effectively and quickly remove the restriction on the rivet after the rivet is fixed, which makes it difficult for the nailing mechanism to be inserted. Quickly drive the positioned rivets.
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