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 4 the material cut out when screwing in the screw can be discharged without any accumulation, the dependent claims reflecting many advantages of further embodiments.
Most electrical appliance manufacturers only require the size and riveting gap to be tested for riveted contact components. There is no clear requirement for riveting strength. Only a few manufacturers perform torsion testing on riveting strength. The torque detection method is as follows: use a saw blade to open a one-shaped groove on the rivet head of the riveted contact element, and then insert a torque wrench into the one-shaped open groove to rotate, and measure the torque value. Because most of the electrical contacts are made of copper-silver alloy, the strength is low, and it is easy to slip during the test, and when a saw blade is used to open the one-shaped groove, the width and depth cannot be accurately positioned, so the measured value fluctuates greatly. , has always been an unsolvable technical problem in the industry.
In order to solve the problem of poor waterproof performance of the existing rivets, Guangdong Yueluo Hardware Industry Co., Ltd. provides a waterproof rivet. By arranging a figure-eight waterproof part for waterproofing on the lower end surface of the waterproof cap, when the object is riveted, The waterproof cap is subjected to the pulling force of the rivet rod and the supporting force of the object. The pulling force and the supporting force cause the waterproof cap to generate stress, which in turn causes the waterproof part of the waterproof cap to be micro-deformed in the closest contact with the object, so as to achieve a good sealing effect.
An elastic cylindrical pin assembling device, the assembling device includes an adapter handle, a punching needle, an elastic piece, a fixed sleeve and a telescopic sleeve, the adapter handle and the fixed sleeve are fixedly connected, and the punching needle is inserted into the adapter handle and fixed Inside the sleeve and its upper end is pressed against the adapter handle, the lower end of the punch needle is also inserted into the fixed sleeve and moves relative to the fixed sleeve in the up and down direction when the adapter handle pushes it to move up and down, the fixed sleeve A reset spring is also set between the punch and the punch, the lower end of the fixing sleeve has an insertion hole for the elastic cylinder pin, that is, a working cavity, and the lower end of the punch needle is also provided with a push fit for the upper end of the elastic cylinder pin. the positioning boss. When the elastic cylindrical pin assembling device is used, after assembling an elastic cylindrical pin, the elastic cylindrical pin needs to be re-installed into the fixed sleeve, which cannot realize continuous assembly and has low assembly efficiency.
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