What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
In the process of driving the car, it is inevitable to use the brake frequently, which will cause the gap between the brake drum and the friction pad of the car to become larger. Therefore, it needs to be adjusted in time, otherwise, the hidden danger of unsafe driving will be buried due to the excessive braking distance and the out-of-round brake drum. Therefore, motor vehicles must be equipped with automatic adjustment arms. In the existing automatic adjustment arm, the worm inside the housing is limited by the spring pad, the spring and the spring cover, and the end face of the spring pad is directly in contact with the worm, and the rotation of the worm is inflexible due to frictional resistance during rotation.
Half round head rivets are mainly used for riveting occasions with large lateral loads, and are the most widely used. Flat cone head rivets are often used in riveting occasions with strong corrosion such as ship hulls, boiler water tanks, etc. Countersunk head and 1200 countersunk head rivets are mainly used for riveting occasions where the surface must be smooth and the load is not large. Half countersunk head and 1200 half countersunk head rivets are mainly used for riveting occasions where the surface must be smooth and the load is not large. Flat head rivets are used for riveting occasions with general load. 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 small loads. 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 small loads. Tubular rivets are used for riveting of non-metallic materials without load. Nameplate rivets are mainly used for riveting nameplates on machines and equipment.
Electrical contact element is a kind of low-voltage electrical products and household electrical products widely used in switches, relays, thermostats, circuit breakers, contactors, controllers, timers, etc. There are mainly three types of electrical contact elements. 1. Riveting parts , riveting the rivet on the copper piece; 2. Welding piece, welding the sheet contact on the copper piece; 3. Stamping piece, punching the composite tape into components. Existing rivet contacts on the market at present are usually all made of precious metals, such as a simple metal matrix such as gold or silver. Its electrical contact performance is limited by a single metal material, and its electrical contact performance is poor; and due to certain requirements for metal purity in production, production efficiency is low, and production costs are high, resulting in the production of products that cannot be sold on a large scale in the market. and application.
At present, with the development of my country's railway industry, many railway fastener systems involve T-bolts. The structure is shown in Figure 1. The dimensions that need to be inspected are head width A, head length B, and head straight table height. C. The height of the head slope D, the total length of the bolt E, and the major diameter of the bolt F. Due to the irregular shape of these places to be inspected, the measurement is difficult. The measurement of general measuring tools is not only slow, but also difficult to control human errors, resulting in some extreme upper limits and There are disputes and misjudgments about the size of the extreme lower limit when judging qualified and unqualified.
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