Service HotlineSubject content and scope of application This technical requirement specifies the technical requirements for the manufacture, installation and inspection of high-strength bolted joints of mobile machinery and equipment. Contents not specified in this technical requirement shall be implemented in accordance with relevant national standards. This technical requirement applies to mobile machinery steel structures that require high-strength bolted connections. This technical requirement applies to quality control and construction methods for in-plant and on-site installations. 2. Joint surface treatment 2.1 For friction type high-strength bolt connections, the joint surfaces at the joints are required to be in close contact with each other and have a sufficient friction coefficient. When the design drawing does not specify the treatment requirements for the joint surface, the treatment shall be carried out according to the following regulations: sandblasting or shot blasting the joint surface of high-strength bolts, remove impurities such as rust and oil stains on the surface, and reach the Sa2.5 standard , the roughness is 50 ~ 75μm, and the friction coefficient shall not be lower than 0.40. When there are regulations in the drawings, follow the regulations in the drawings. 2.2 The friction surface of the treated high-strength bolt connection should take protective measures to prevent contamination with dirt and oil. It is strictly forbidden to make any marks on the friction surface of the high-strength bolt connection. During storage in the factory, or during transportation, to the installation site, special precautions should be taken to prevent contamination of the connection surfaces. The installation unit should pay special attention to protecting the cleanliness and friction surface characteristics of the connecting plate of the high-strength bolt and the connecting surface of the parent body. It is not allowed to use a grinder to grind the connecting surface of the connecting plate and the connecting surface of the parent body. 3 Inspection of the anti-slip coefficient of the friction surface of high-strength bolts The inspection of the anti-slip coefficient should be based on the steel structure manufacturing batch, and each 2000t of a single project is regarded as a manufacturing batch, and those less than 2000t are regarded as a batch. When two or more surface treatment processes are selected, each surface treatment process needs to be inspected. Each batch of three groups of specimens. If the connection is diffused to an external enterprise, each corresponding enterprise shall conduct an anti-slip coefficient test. 3.1 The test piece used for the anti-slip coefficient test should be processed by the factory or the diffusion enterprise. The test piece and the representative steel structure member should be of the same material, produced in the same batch, using the same friction surface treatment process and have the same surface state. And use the same batch of high-strength bolt connection pairs of the same performance level and store them under the same environmental conditions. The anti-slip coefficient test is carried out according to the test method of GB50205 Code for Acceptance of Construction Quality of Steel Structure Engineering. 3.2 The minimum value of the anti-slip coefficient inspection must be equal to or greater than the design specified value. When the above specified values are not met, the friction surface of the component should be reprocessed. The friction surface of the treated component is re-inspected. 4. Connection and installation of friction type high-strength bolts for steel structures 4.1 Preparations before installation 4.2 Select qualified bolts, nuts and washers. The guarantee period for the torque coefficient of the connecting pair is six months from the date of delivery. 4.3 Bolts, nuts and washers in the following cases are unqualified products and are prohibited from being used. a. The source (manufacturer) is unknown; b. The mechanical properties are unknown; c. The torque coefficient k is unknown; d. Defective; e. No performance test report attached; f. Mixed with other batches of bolts; g. Bolts with insufficient length, that is, the bolt head does not show the end face of the nut after tightening. Generally, the length of the end face of the nut to be taken out is 2 to 3 threads. h. The torque coefficient of the connecting pair exceeds the warranty period. Special attention should be paid to waterproofing during transportation and storage. 4.4 Before the construction of the large hexagonal head high-strength bolts, the torque coefficient of the high-strength bolt connection pair should be re-inspected according to the factory approval. Each batch of 8 sets should be re-inspected. Less than or equal to 0.010. The re-inspection method of the torque coefficient shall be carried out in accordance with the provisions of GB50205 Code for Acceptance of Construction Quality of Steel Structure Engineering. The installation of high-strength bolts should be carried out within a short period of time after the test.
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.
The main technical problem solved by Guangdong Yueluo Hardware Industry Co., Ltd. is to provide a fixing screw for installation, so as to provide a PCB fixing method with convenient operation, reliable connection and low production cost. In order to solve the above-mentioned technical problems, a technical solution adopted by Guangdong Yueluo Hardware Industry Co., Ltd. is to provide a fixing screw for installation, which includes a screw body, the axial surface of the screw body is formed with extended screw teeth, and the screw body is The bottom has a hemispherical screw tail, the top of the screw body is provided with a screw head, and the upper surface of the screw head is provided with a slot. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the screw body is composed of an upper tapered rod and a lower cylindrical screw rod, and the tapered rod is an inverted cone. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the diameter of the circular upper surface of the inverted cone of the taper rod is equal to the diameter of the screw mounting hole. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the screw further has a washer, the washer is arranged between the screw head and the screw body, and the washer is a cylinder. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the lower surface of the cylindrical washer has a plurality of teeth, and the teeth are along the edge of the connection between the upper surface of the inverted cone of the tapered rod and the washer Ribs formed by extending outwards. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the teeth of the washer are in contact with and pressed against the PCB board. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the protruding strip is an arc-shaped or straight-shaped structure. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the notch opened on the upper surface of the screw head is a slot. [0018] According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the notch provided on the upper surface of the screw head is a cross groove. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the fixing screw is integrally formed with conductive material. Compared with the existing technology, the fixing screws for installation designed by Guangdong Yueluo Hardware Industry Co., Ltd. can not only ensure the accuracy of the PCB installation position, but also can be installed easily and reliably, which greatly reduces the manufacturing cost and waste of metal materials.
Now people often use spring washers to lock nuts and bolts, spring washers, generally stainless steel and carbon steel non-closed spiral washers, under the nut, above the flat washer, increase the friction between the nut and the bolt, used to prevent The nut is loose to prevent vibration from loosening
Alloy Steel Nuts Hexagon Nuts (GB6170/DIN934, GB6175), Flange Nuts (GB6177/DIN6923) Round Nuts (GB812), Small Round Nuts (GB810), American Square Nuts, American Hex Nuts (NI/MEB18.2.2), Heavy Duty Nuts (Metric, US). Specifications: 5/16-4. Nut Specifications Nut specification table is to unify all kinds of nuts in detail, and use the table to subdivide some specifications of nuts. There are many types of nuts, and there are nuts of different materials. Each type of nut has different specifications, and each type of screw also has its mechanical properties and functions.
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