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 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.
The hexagonal flange surface nut mainly includes a nut body, a flange surface is fixed at one end of the nut body, and a cap is fixed at the other end of the nut body. Has good sealing and corrosion resistance. The hexagonal flange surface nut mainly includes a nut body, a flange surface is fixed at one end of the nut body, and a cap is fixed at the other end of the nut body; since the cap is set on the nut body, it has the Better sealing can effectively prevent rain, moisture, dust and other harmful substances from immersing in the nut body, prevent the nut body from rusting, and greatly extend the service life of the hexagonal flange nut.
When the mechanical components are installed on the concrete foundation, the J-shaped and L-shaped ends of the bolts are embedded in the concrete for use. The tensile capacity of the anchor bolt is the tensile capacity of the round steel itself. The size is equal to the cross-sectional area multiplied by the allowable stress value (Q235B: 140MPa, 16Mn or Q345: 170MPA), which is the allowable tensile capacity at the time of design. The anchor bolts are generally made of Q235 steel, which is smooth and round. Rebar (Q345) is strong, and the thread of the nut is not as easy to be round. For light round anchor bolts, the burial depth is generally 25 times its diameter, and then a 90-degree hook with a length of about 120mm is made. If the bolt diameter is large (such as 45mm) and the buried depth is too deep, a square plate can be welded at the end of the bolt, that is, a large head can be made (but there are certain requirements). The burial depth and hook are all to ensure the friction between the bolt and the foundation, so as not to cause the bolt to be pulled out and damaged.
concealed screw fastener includes a washer, a screw and a shield, one end of the screw is provided with an end cap, the screw penetrates the washer and the end cap is supported on the washer, and the shield covers the end of the screw The cap is peripheral and connected to the gasket. When in use, firstly pass the screw through the washer and then drive it into the screw hole of the connected piece, and then cover the shield on the outer circumference of the end cap of the screw and connect it with the washer.
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