What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
flat washer is a part that is placed between the connected part and the bolt to protect the surface of the connected part from being scratched by the nut and to disperse the pressure of the nut on the connected part. At present, a flat washer in the prior art generally includes a washer body; the washer body has a bolt hole in the middle for a bolt to pass through. Although the flat washer of the above structure has a simple structure, it still has a disadvantage. When the flat washer is cushioned between the connected part and the bolt, the bolt head is usually exposed outside the connection part, so the bolt head is easy to It is damaged under the impact of external force, thus affecting its fixing effect.
When the nut is tightened on the stud, there will inevitably be an empty upstroke. That is, when the nut has not reached the part that needs to be tightened, the nut needs to be twisted on the non-locking (working) part of the front end of the stud by hand or tool, so that the nut runs along the axial direction of the stud and reaches the part to be locked. . When the idling stroke of the thread at the front end of the stud is long or the thread pitch is small, the idling stroke before locking will waste a lot of time, resulting in a huge occupation of personnel or tools.
When the mold is manufactured, many positioning pins need to be installed to fix the relative position between the two parts. The positioning pins are usually sunk into the positioning pin holes on the mold. Since the mold needs to be pulled out frequently during assembly, in order to Remove the parts and make corrections. At the same time, the mold also needs to pull out the positioning pins during maintenance to remove the damaged parts for maintenance. Therefore, the workload of pulling the pins is large. The existing methods are: 1) When installing the pins, The operator uses a self-made long screw that matches the threaded hole of the pin to screw it into the pin, and then aligns the pin hole with a hammer to hit the screw to make the pin snap in, and then screw the screw out by hand. The disadvantage is: on the one hand, the hammer hits the screw It is easy to cause the screw to be damaged or deformed, and it cannot be used normally. On the other hand, it is labor-intensive to remove the screw by hand and may not be able to be removed; 2) When pulling out the pin, the operator will screw the screw into the pin and use force directly or with pliers To pull out a screw, a few companies use a large pin puller to pull it out. The disadvantage is that it is too laborious and time-consuming to pull out by hand or with pliers. Even if a large pin puller is used, the weight of the pin puller itself is large. , it is inconvenient to use.
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 an ordinary screw, and the height is 6 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.
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