Service HotlineYueluo 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 3 the material cut out when screwing in the screw can be discharged without any accumulation, the dependent claims reflecting many advantages of further embodiments.
There are two types of bolt detection: manual and machine. Manual is the most primitive and the most commonly used consistent detection method. In order to minimize the outflow of defective products, general production enterprise personnel inspect the packaged or shipped products by visual means to exclude defective products (defects include tooth damage, mixed materials, rust, etc.). [2] Another way is automatic machine inspection, mainly magnetic particle inspection. Magnetic particle inspection is to use the interaction between the leakage magnetic field at the defect of the bolt and the magnetic powder, aiming at the difference between the magnetic permeability of the bolts (such as cracks, slag inclusions, mixed materials, etc.) and the magnetic permeability of steel, these materials are discontinuous after magnetization. The magnetic field at the place will be turbulent, and a leakage magnetic field will be generated on the surface of the workpiece where part of the magnetic flux leaks, thereby attracting the magnetic powder to form the magnetic powder accumulation at the defect—magnetic traces. The accumulation of these magnetic powders is observed and explained, and the purpose of rejecting defective products has been achieved.
Referring to Figure 1, one end of the existing insert nut 1' is embedded in the injection molded part 2', and the other end is exposed to the injection molded part 2'. The insert nut 1' has opposite lower and upper end surfaces in the axial direction. The end face of one end of the insert injection molded part 2' is the lower end face. In order to reduce the resistance during hot pressing, the connection between the inner wall surface and the lower end surface of the insert nut 1 ′ is provided with an inclined surface. However, when the embedded nut 1' of this structure is hot-pressed, the hot melted glue will generate a shunt that rises along the slope, and then a convex peak is formed in the screw hole of the embedded nut 1', and the convex peak occupies the screw. The space in the hole prevents the screw 5' from being completely screwed in; at the same time, due to the shunting of the hot solder, the knurling of the inner nut 1' near the upper end face cannot be filled with the solder, which makes the inner nut 1' and the inner nut 1' and The injection part 2' is not firmly embedded. Therefore, the locking strength of the existing insert nut 1 ′ and the screw 5 ′ after being hot-pressed is relatively low.
The screw and nut disassembly and assembly tool of Yueluo also includes a rotating rod, a sleeve and a fixed rod fixedly connected to the sleeve rod at one end, and the other end of the fixed rod is connected with one end of the rotating rod to make the rotation The rod can be rotated around the connection point, and the sleeve for accommodating nuts or screws is fixedly connected with the other end of the rotating rod; rotating the rotating rod makes the sleeve head and the opening of the sleeve opposite , by keeping the nut or screw in the sleeve fixed while the corresponding screw or nut in the sleeve head rotates, so as to achieve simultaneous force and disassembly of the screw and the nut.
At present, the washing machines used in the domestic market, especially the large-capacity washing machines, have high rotational inertia due to their large washing capacity. The wear between the input shaft and the clutch sleeve will cause the increase of the axial clearance. There will be strong shaking and loud noise, which will increase the wear and tear and affect the service life. In the prior art, the wave washer is used to prevent loosening and buffer shock, so that the gap between the input shaft and the clutch sleeve will not increase due to the wear of the two, which plays the role of automatic gap compensation, so as to ensure the clutch Smooth rotation, low noise and light wear ensure the reliable service life of the clutch.
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