What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Yueluo relates to a self-tapping screw according to the preamble of claim 1. A self-tapping screw is known from EP0623759B1, the ratio of the outer diameter to the smaller diameter of the self-tapping screw is about 1.25-1.5, the ratio of the outer diameter to the pitch lead is about 1.5-1.6 and the thread The flank angles of , are < 50° and ≥ 35°. EP0433484B1 proposes a self-tapping screw whose thread is provided with cutting teeth of approximately arcuate design, and the cutting edge and the thread crest are at the same horizontal position and are set in opposite directions. One purpose of Yueluo is to realize a general type of self-tapping screw so that it can be screwed particularly easily into holes drilled in concrete or other materials such as bricks and the like. According to Yueluo, this object is achieved by the features in the characterizing part of claim 1, and surprisingly, it has been found that the parallel arrangement of the flanks, ie with a flank angle of about 0°, will make screwing particularly easy when screwing in , especially if the diameter of the hole varies within an allowable tolerance. One reason may be due to the fact that there is no lateral pressure on the material screwed into the thread, even if threads of different depths are cut in concrete or other materials such as brick, chipped plywood, or hardwood. The thread cuts into the material over its entire width by cutting grooves. In particular according to the embodiment of claim 13 the material cut out when screwing in the screw can be discharged without any accumulation, the dependent claims reflecting many advantages of further embodiments.
The traditional gasket is a single-piece gasket that works independently. This gasket mainly relies on friction to achieve the anti-loosening effect. The new washer is composed of two pieces. Its unique embedded structure changes the way that the traditional washer mainly achieves anti-loosening through friction. Instead, it adopts the most advanced anti-loosening technology in the world and uses the tension between the two gaskets to achieve. The dual effect of anti-loosening and tightening.
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-tight 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 ordinary screws, and the height is 3 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.
At present, in the power industry, for the fixing of terminals, most of the terminals are directly locked to the fixing screws using U-shaped clips. However, since the contact surface often cannot reach the level of flatness, it will cause difficulties in locking, and it will take a long time. Easy to loose and fall off. Although the use of spring clips is effective, due to the influence of its own width, the use of spring clips is not very extensive. Contents of the utility model The purpose of Yueluo Guangdong Yueluo Hardware Industry Co., Ltd. is to provide an automatic locking screw for fixing the U-shaped clip. In order to achieve the above purpose, Yueluo adopts the following technical solutions: an automatic locking screw. From bottom to top, there are screw head, screw rod and nut with external thread. The screw rod is a hollow screw rod, and the hollow screw rod is on both sides. Long holes are respectively provided, the width of the long holes is smaller than the inner diameter of the hollow screw rod, a spring is arranged in the inner cavity of the hollow screw rod, the upper end of the spring is provided with a plug, and the two wings of the plug protrude out of the hollow screw rod through the long hole. The spring described by Yueluo is not less than the length of the hollow screw rod in the free extension state. The distance between the two wings of the plug described by Yueluo is greater than the diameter of the nut. Yueluo adopts Guangdong Yueluo Hardware Industry Co., Ltd., which can easily realize the automatic locking of the U-shaped clamp, and can be adjusted according to the thickness of the U-shaped clamp to ensure the close contact between the U-shaped clamp and the connecting screw.
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