What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Guangdong Yueluo Hardware Industry Co., Ltd. discloses a low-carbon steel rivet nut fastened to a thin-walled and thin-plate fastener. The rivet nut fastener is composed of a brim, a deformed skirt, and a threaded hole. Using low carbon steel cold extrusion, the brim is formed by cold heading, the deformed skirt is extruded in the concave die, and the thread hole of the nut tapping skirt is extruded at the lower end of the deformed skirt. It is characterized in that there are fish teeth under the brim; the outer side of the lower end of the threaded hole has a lead angle; the cross-section of the thread of the inner wall of the threaded hole is an isosceles trapezoid, and the upper bottom of the trapezoid is a concave solitary shape, and the fastener does not need to be welded. , Single-sided riveting, easy operation and firm connection.
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 11 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.
There are two typical pin shearing fixture tooling, among which the traditional fixture shown in Fig. 1 is more complicated and consists of fixture, spacer, washer and shearing block guide post, hardened bushing, shearing block and so on. The cylindrical pin is installed in the hardened bushing, and the axial load is applied through the shear block to complete the shear test. The fixture is complicated in manufacture and has many consumables, because the size of the hardened bushing is similar to that of the cylindrical pin. , and to keep the notch of the cylindrical pin upward, it is difficult to install before the test, and the broken cylindrical pin after the test remains in the hardened bushing and is difficult to remove.
According to the design of the screw washer 110 , when the metal piece 120 and the metal piece 130 are disassembled, after the screw 100 is loosened, the screw washer 110 is often easily dropped or lost, causing trouble for maintenance. Especially when replacing parts at the user end, if the screw washer is loose, it cannot ensure that the user can install it correctly; if the screw washer is lost, it is necessary to purchase new parts, causing a lot of inconvenience.
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