Furniture rice countersunk head hexagonal self-tapping screws Roller-mount screws Self-tapping screws Kitchenware cabinet screws

Wire cutters are widely used tools in electromechanical and other industries, and rivets are widely used standard parts, especially in the manufacturing or maintenance process of the electromechanical industry. Because the currently used wire cutters are mostly used to cut finer steel wires or various wires and twist small screws and nuts. In the process of work, rivets of various specifications are often encountered temporarily. For example, suitable rivets cannot be found at the scene, or other replacements will cause inconvenience to the work, which not only affects the output, but also affects the quality.

The earless retaining ring for the hole is mostly installed in the annular groove on the inner wall of the pipe fitting. The outer diameter of this kind of retaining ring is slightly larger than the diameter of the assembly round hole. When assembling, the earless retaining ring needs to be pressed into the pipe fitting. Since the inner wall of the pipe fitting is relatively smooth, the earless retaining ring is easily skewed in the pipe fitting. It needs to be adjusted several times before entering the annular groove, and the assembly efficiency is low.

Code name and standard number of inch thread commonly used abroad Mark code name country and standard number Remarks BSW standard Wyeth coarse thread series, general purpose cylindrical thread British standard BS 84 inch thread with a profile angle of 55° BSF standard Wyeth fine thread series, General Purpose Cylindrical Thread Whit.S Additional Whit.S Optional Series, General Purpose Cylindrical Thread Whit Non-standard thread with Whitworth profile UN Uniform thread of constant pitch series American standard ANSI B1.1 inch thread with 60° profile angle, with Internal and external threads with standard profile (flat or rounded at random) UNC Coarse thread unified thread UNF fine thread unified thread UNEF superfine thread unified thread UNS① Special series unified thread UNR round The uniform thread profile angle of the arc root constant pitch series is 60° inch thread, UNR, UNRC, UNRF, UNREF, UNRS with arc root are only used for external thread without internal thread UNRC arc root coarse thread Series Unified Thread UNRF Circular Root Fine Thread Series Unified Thread UNREF Circular Root Ultra Fine Thread Series Unified Thread UNRS Circular Root Special Series Unified Thread NPT② Generally used for pipe thread American standard ANSI B1.20.1 Profile angle is 60° Inch Pipe Thread NPSC Pipe Fitting Straight Pipe NPTR Pilot Connection Tapered Pipe NPSM Mechanical Connection Straight Pipe NPSL Lock Nut Straight Pipe NPSH Hose Connection Straight Pipe NPTF Dry Seal Standard Tapered Pipe Thread American Standard ANSI B1.20.3 Type I PTF-SAE SHORT Dry Seal Short Taper Pipe Thread Type II NPSF Dry Seal Standard Fuel Oil Straight Pipe Internal Thread III Type NPS1 Dry Seal Standard General Straight Pipe Internal Thread IV Type ACME③ General Purpose Trapezoid Thread American standard ANSI B1.5 Inch drive thread with 29° profile angle ① Dimensions and tolerances All diameter and pitch combinations other than the standard series are calculated using the same formula as the standard series. ② my country's 60° conical pipe thread GB/T12716-1991 is equivalent to it. ③ACME thread includes two kinds of matching trapezoidal threads, general purpose and centering, of which the general purpose thread has the same performance as the trapezoidal thread specified in my country's standard GB/T5796-1986.

Due to manufacturing and installation errors, the lamp head and its connecting part of the shadowless lamp will drift, which cannot be positioned at any position. Therefore, in the shadowless lamp, the damping force is usually provided by the damping screw to realize the positioning of the lamp cap and its connecting part. The damping screw needs to be able to provide a suitable damping force. The damping force should not be too small to meet the positioning requirements; at the same time, the damping force should not be too large to make the user feel comfortable when moving the lamp head and its connecting parts. In addition, within the normal life range, after the damping screw is worn, it should also be able to provide sufficient damping force to satisfy the positioning of the lamp cap and its connecting part. The damping screw is tightened by the thread, the top pressure disc spring is deformed, and the disc spring presses the friction end to generate frictional force, thereby providing an effective and lasting damping force. The damping force can be realized by adjusting the screw tightness. For the friction ends, there are certain requirements for wear resistance, certain self-lubrication, certain strength, hardness and toughness. At present, the friction end materials in the industry mainly include metals such as brass and tin bronze; non-metals such as nylon and POM. At present, the main disadvantage of the friction end of the damping screw is that it is easy to produce abnormal noise during the friction process for metal materials. For non-metallic materials, deformation is easy to occur and the strength is insufficient.

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