What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The Chinese Patent Application No. 201320368989.2 discloses a pin, which includes a pin body and a cylindrical body part integrally provided with the pin body, a convex tip is provided on the cylindrical body part at one end of the pin body, and the convex The tip is horizontally arranged around the cylindrical body part and protrudes from the surface of the cylindrical body part. The connection between the cylindrical body part and the convex tip is provided with an inclined plane. Although this pin solves the problems of easy loosening and falling off to a certain extent, However, this kind of pin still has the problem of loosening and falling off in the case of bad working conditions and severe vibration.
Fig. 1, Fig. 2, and Fig. 3 show that the rivet nut is cut into the required blank from a chemically treated low carbon steel disc, and the blank is placed in the die, and the upper and lower punches are used for shaping to obtain a shaped blank. , and then put the shaped blank in the die, use the punch punch to cold-head out the required brim blank (1) and the deformed skirt (2), and then use the punch punch in the die to continue Cold heading out the brim blank (1) and the deformed skirt (2). Then put the semi-finished material into the concave die and use the punch of the punch to continue to squeeze the threaded hole (3) of the nut tapping skirt, and then put the semi-finished blank into the concave die and use the upper punch and the lower sleeve to drop it. material. There are fish teeth (6) below the brim; the outer side of the lower end of the threaded hole is provided with a chamfer (5); 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 arc (4), In this way, the riveted object is firmly connected to the rivet nut.
According to the force of the connection, it is divided into ordinary and hinged holes. According to the shape of the head: there are hexagonal head, round head, square head, countersunk head and so on. Among them, the hexagonal head is the most commonly used. Generally, countersunk heads are used where connections are required. The English name of the riding bolt is U-bolt. It is a non-standard part. The shape is U-shaped, so it is also called a U-bolt. There are threads on both ends that can be combined with nuts. It is mainly used to fix tubular objects such as water pipes or sheets such as automobile plates. Springs are called riding bolts because of the way they fix things like a person rides a horse. According to the length of the thread, it is divided into two categories: full thread and non-full thread. According to the thread type, it is divided into two types: coarse thread and fine thread. The coarse thread type is not displayed in the bolt mark. The bolts are divided into eight grades: 3.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, and 12.9 according to their performance grades. Among them, the bolts above grade 8.8 (including grade 8.8) are made of low-carbon alloy steel or medium-carbon steel and are heat-treated (quenched). + Tempering), commonly known as high-strength bolts, and below grade 8.8 (excluding 8.8) are commonly known as ordinary bolts. Ordinary bolts can be divided into three grades: A, B, and C according to the production accuracy. Grades A and B are refined bolts, and grade C is rough bolts. For connecting bolts for steel structures, unless otherwise specified, they are generally ordinary rough grade C bolts. There are differences in the processing methods of different grades. Usually the corresponding processing methods are as follows: ① The bolts of grade A and B bolts are processed by lathes, with smooth surfaces and accurate dimensions. High, rarely used; ②C-grade bolts are made of unmachined round steel, the size is not accurate enough, and its material property grade is 4.6 or 4.8. The deformation is large during shear connection, but the installation is convenient and the production cost is low. It is mostly used for tensile connection or temporary fixation during installation.
As shown in Figures 1 and 2, Yueluo is an automatic locking screw. From bottom to top, there are screw head 1 with external thread, screw rod and nut 3. The screw rod is a hollow screw rod 2, and the hollow screw There are long holes 7 on both sides of the rod 2, the width of the long hole 7 is smaller than the inner diameter of the hollow screw rod 2, and a spring 4 is arranged in the inner cavity of the hollow screw rod 2, and the spring 4 is not smaller than the hollow screw rod 2 in the free extension state. The upper end of the spring 4 is provided with a plug 5, the distance between the two wings 6 of the plug 5 is greater than the diameter of the nut 3, and the two wings 6 of the plug 5 protrude out of the hollow screw rod 2 through the long hole 7. When using the Yueluo, you only need to compress the spring through the two wings, insert the U-shaped clip after the neutral position is exposed, and then release the two wings, the spring will automatically return and compress the U-shaped clip, which is easy to use, safe and reliable. Claim 7. A self-locking screw, from bottom to top, is a screw head, a screw rod and a nut provided with an external thread, characterized in that the screw rod is a hollow screw rod, and both sides of the hollow screw rod are respectively provided with Long hole, the width of the long hole is smaller than the inner diameter of the hollow screw rod, the inner cavity of the hollow screw rod is provided with a spring, the upper end of the spring is provided with a plug, and the two wings of the plug protrude out of the hollow screw rod through the long hole.
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