Service HotlineAs my digital TV technology becomes more and more mature, more and more people with digital-to-analog signal conversion function enter people's lives. Therefore, the number of production and processing is also increasing day by day. There are many requirements for the form, reliability and cost of PCB fixing screws in production. One of the existing fixing methods is to fix by means of bolts and nuts. The operation steps are to place the PCB board on the inner threaded copper column connected to the casing, and pass through the bolts with fine teeth. Screw holes on the PCB board, and then fix them on the copper posts with nuts. The connection method of this solution is reliable, but its manufacturing cost is high, and the copper column and the metal shell need to be screwed together, resulting in low production efficiency and high cost. In addition, there is also a common way that the PCB is supported by a plastic column, and the self-tapping screw is passed through the screw hole on the PCB board, and the PCB board and the metal bottom shell are connected by the self-tapping thread on the screw. The main disadvantage of this solution is that after the screw is fixed on the metal shell, the screw head is exposed at the bottom of the machine. If the user is not careful during use, the hand scratching phenomenon will occur, which will bring changes and harm to the user's use. . And when the machine slides on the desktop, if the screw head is too exposed, it will scratch the desktop. Therefore, how to provide a PCB fixing method with convenient operation, reliable connection and low production cost is a technical problem to be solved urgently in the industry.
1. The expansion phenomenon of the spring washer is generally not the problem of the spring washer itself. 2. The spring washer with the expansion ring must be subjected to a radial external tension. The external tension is derived from the tightening axial force generated by the tightening torque. The chamfer creates a radial component of the axial clamping force, which expands the opening of the spring washer. The smaller the chamfer diameter, the greater the possibility of ring expansion. 4. Adding a flat washer between the nut and the spring washer helps to slow down or prevent the expansion of the ring, but the flat washer is too thin or too soft. Prevent ring expansion 5. The reason for the hydrogen embrittlement fracture of spring washers is generally due to unreasonable heat treatment process and the failure of hydrogen removal treatment after electro-galvanizing. A large number of tests and long-term practical experience have confirmed the above analysis.
square nut described by Guangdong Yueluo Hardware Industry Co., Ltd. includes a nut body 1, the nut body 1 is in the shape of a cube, the side length is 7.6mm, and the height is 2.4mm. The upper and lower ends of the nut body 1 are respectively set. There are circular protrusions 2 and circular protrusions 3 with a height of 0.25mm, and the circular protrusions 2 and the circular protrusions 3 are respectively tangent to the upper and lower surfaces of the nut body 1 in a square shape. A through hole 4 is provided in the middle of the shaped protrusion 2 and the circular protrusion 3, and runs through the nut body 1. The opening of the through hole 1 is provided with a chamfer 5 of 30°, and a thread 6 is provided on the inner wall of the through hole 4. , the circular protrusion 2 is provided with a number of strip-shaped protrusions 7 along the circumference inward to the opening of the through hole 4. The number of the strip-shaped protrusions 7 can be arbitrary, and the ideal number is 26, and the through hole 4 is open. There are several strip-shaped grooves 8 at the circumference of the circular protrusion 3. The number of strip-shaped grooves 8 can be arbitrary, and the ideal number is 26. The circular protrusions 2 and the circular protrusions 3 There is a chamfer 9 of 15° extending outward to the prism of the nut body 1 . The production of square nuts described by Guangdong Yueluo Hardware Industry Co., Ltd. is basically the same as the traditional nut process. The key point is to use a punching machine to punch out circular protrusions on both ends. High, and the circular protrusion 2 is punched again to make a bar-shaped protrusion 7, and at this time, the height of the circular protrusion 2 is consistent with the plane height of the circular protrusion 3, and the circular protrusion 3 is formed by stamping. groove 8. The contact surface of the nut body 1 is increased by providing circular protrusions 2 and circular protrusions 3 on the upper and lower end surfaces of the nut body 1, and respectively providing a bar-shaped protrusion 7 and a bar-shaped groove 8 at the two circular protrusions. Therefore, the friction between the nut body 1 and the fastener is effectively increased, and a good fastening effect is achieved.
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.
Reference standard GB 90 Fastener acceptance inspection, marking and packaging GB 196 Basic dimensions of ordinary threads (1～600mm in diameter) GB 197 Tolerance and fit of ordinary threads (1～355mm in diameter) GB 230 Test method for Rockwell hardness of metals GB 699 High-quality carbon Plain structural steel technical conditions GB 1237 Marking method of fasteners GB 5267 Electroplating layer of threaded fasteners GB6394 Determination of average grain size of metals
We have many years of experience in the production and sales of screws, nuts, flat washers, etc. The main products are: GB96 stainless steel enlarged flat washers, hexagonal half-threaded bolts, thin flat washers, flat head rivet nuts and other products, we can provide you with suitable fastening products piece solution.
