What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
As the requirements for the use of electrical appliances in various industries continue to increase, the testing specifications for the performance of various components in electrical appliances are also constantly improving. Riveted contact elements are used in various relays, contactors, small switches, thermostats, etc. in low-voltage electrical appliances. The structure of the riveted contact element generally includes a contact base and a rivet riveted to the contact base. The rivet includes a rivet head and a rivet top, the structure of which is shown in FIG. 1 .
The fixing screw proposed by Guangdong Yueluo Hardware Industry Co., Ltd. has a screw body 1, and the axial surface of the screw body 1 is formed with extending screw teeth 6, and the axial surface is a column along the central axis direction of the cylinder of the screw body 1. The body surface has a hemispherical screw tail 7 at the bottom, and a screw head 2 at the top. The upper surface of the screw head 2 is provided with a slot (not shown). The screw body 1 is composed of the upper tapered rod 4 and the lower cylindrical screw 5. The tapered rod 4 is an inverted cone, the diameter of its circular upper surface and the diameter of the screw mounting hole 10. equal. The fixing screw also has a washer 3, the washer 3 is arranged between the screw head 2 and the screw body 1, the lower surface of the cylindrical washer 3 has a number of teeth 8, the teeth 8 are along the The upper surface of the inverted cone of the tapered rod 4 and the edge of the washer 3 are connected to form a straight convex strip 15 extending outward; the convex strip 15 can also be designed in an arc shape. The fixing screws for installation proposed by Guangdong Yueluo Hardware Industry Co., Ltd. can be made of metal materials in one piece. As shown in Figure 3, it is a schematic diagram of the installation of Guangdong Yueluo Hardware Industry Co., Ltd. for PCB board fixing. When installing, first pass the screw body 1 of the fixing screw through the mounting hole 10 and the copper column 11 provided on the PCB board 9, so that the tail 7 of the screw reaches the mounting hole 13 on the casing 12, and then use the tightening tool 14 to insert the screw At the notch on the top of the head, forcefully press the inverted cone design taper rod 4 of the screw body 1 into the mounting hole 10, so that the tail 7 passes through the mounting hole 13. Due to the outer diameter D at the bottom of the taper rod and the screw mounting hole The aperture size of 10 is equal, and the fixing screws are pressed and fixed, so that the PCB board 9 can be automatically corrected in the process of fixing its front, back, left and right deflections, and the accuracy of the installation position of the PCB board 9 can be ensured. As shown in Figure 4, after the fixing screw is screwed into the casing, the washer 3 is fully contacted and pressed on the PCB board 9, and the PCB board 9, the copper column 11 and the casing 12 are firmly connected together without sliding. . The teeth 8 on the washer 3 are in full contact with the surface of the PCB board 9, so that a ground wire path is set up between the PCB board 9 and the casing 13 by the metal fixing screw 1, thereby ensuring that the PCB board 9 is fully grounded , the design of the teeth 13 on the washer 3 also has a non-slip function. The fixing screws for installation designed by Guangdong Yueluo Hardware Industry Co., Ltd. make use of the cooperation, friction and electrical conductivity in the mechanical connection, which fully guarantees the firm installation of the PCB board and the chassis and the good grounding of the PCB board. Moreover, the ellipsoid tail of the fixing screw The surface is relatively smooth, even if the mounting holes are exposed, it will not cause scratches on the hands and desktop. The above is only the embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., and does not limit the scope of Guangdong Yueluo Hardware Industry Co., Ltd., any equivalent structure made by using the contents of the description and drawings of Guangdong Yueluo Hardware Industry Co., Ltd. or etc. Effective process transformation, or direct or indirect application in other related technical fields, are also included in the protection scope of Guangdong Yueluo Hardware Industry Co., Ltd.
In the prior art, the screw suction device can be implemented in the following two ways. One is to use a magnet to magnetize the electric bit head, and the electric bit head is used to approach the screw, and the screw is stuck by the electric bit head, so that the function of picking up the screw can be realized; The vacuum generator is used to form a negative pressure in the screw guide groove, and the screw is sucked into the tube to realize the screw pickup. The disadvantage of this solution is that in the process of picking up the screws, the grooves of the screws cannot be aligned, which leads to the deviation or leakage of the screws. The disadvantage of this solution is that the screw with an aspect ratio of less than 1.8 is prone to suction and skew, and the stability is not high. It can be seen that the existing technology still needs to be improved and developed.
Rivet riveting has the advantages of simple process equipment, shock resistance, impact resistance, uniform force transmission, firmness and reliability, etc. The key parts of mining equipment such as skips, cages, dumpers, and mine trucks are all connected by rivet riveting. The quality of rivet riveting directly affects the product quality, working performance and service life of mining equipment. The number of rivets used in mining equipment is huge. Each mining equipment requires one hundred or hundreds of rivets, and they are used in mining equipment. The specifications of the rivets in the equipment are large, and the riveting process of hot riveting is mostly used. The riveting tools required are riveting machines and rivet molds.
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