Materials and main equipment: 1.1 Bolts, nuts and washers shall be accompanied by quality certificates and shall comply with design requirements and national standards. 1.2 The high-strength bolts should be stored in categories according to their specifications, and should be protected from rain and moisture. Do not use if the bolts and nuts are not matched and the threads are damaged. If the bolts, nuts and washers are corroded, the tightening axial force should be sampled and used only after meeting the requirements. Bolts, etc. shall not be contaminated by soil or oil, and shall be kept clean and dry. It must be used in the same batch according to the batch number, and must not be mixed or mixed. 1.3 Main tools: electric torque wrench and controller, manual torque wrench, manual wrench, wire brush, tool bag, etc. 2 Operating conditions: 2.1 Friction surface treatment: The friction surface is treated by sandblasting, grinding wheel grinding and other methods, and the friction coefficient should meet the design requirements (a requirement is that the Q235 steel is above 0.45, and the 16 manganese steel is above 0.55). The friction surface wood is allowed to have residual iron oxide scale. The treated friction surface can generate red rust surface and then install the bolts (generally stored in the open air for about 10d). The sandblasted friction surface can be installed without rusting. When grinding with a grinding wheel, the grinding range is not less than 4 times the diameter of the bolt, the grinding direction is perpendicular to the direction of force, and the friction surface after grinding should be free of obvious unevenness. The friction surface should be prevented from being polluted by oil or paint. If polluted, it should be cleaned thoroughly. 2.2 Check the hole size of the bolt hole, the burrs on the edge of the hole must be removed. 2.3 The bolts, nuts and washers of the same batch number and specification should be packaged for use. 2.4 Electric wrenches and manual wrenches should be calibrated.
ANSI B1.1 Thread Pitch Comparison Table Nominal Diameter (inch〖mm〗) Coarse Thread Pitch (UNC) Fine Thread Pitch (UNF) Ultra Fine Thread Pitch (UNEF) Drilling Diameter (Coarse Thread) Drilling Diameter (Fine Thread) #0 0.060 〖1.524〗 80 1.2 # 1 0.073 〖1.5 1.5 # 2 0.086 〖2.8 # 3 0.099 〖2.515〗 48 56 2.0 2.1 # 4 0.112 〖2.4 # 5 0.125 〖 3.175〗 40 44 2.5 2.6 # 6 0.138 〖3.50〗 32 40 2.7 2.9 # 8 0.164 〖4.166〗 32 36 3.4 3.5 # 10 0.190 〖4.0 # 12 0.216 〖5.486〗 24 28 32 4.5 4.6 1/4 6.35 20 28 32 5.1 5.4 5/16 10.7 11.5 9/16 〖14.288〗 12 18 24 12.3 13.1 5/8 〖15.875〗 11 18 24 13.5 14.7 3/4 〖19.05〗 10 16 20 16.7 17.5 7/8 〖22.125 2.4 9 14 〗 8 12 20 22.2 23.4 The pitch is expressed by the number of teeth per inch, such as: 11 teeth per inch, then the pitch=25.4/11=2.309mm. The unit of pitch in the table is the number of threads per inch. The hole diameter is the recommended hole size for tapping, in millimeters.
Regardless of stainless steel plate or heat-resistant steel plate, austenitic steel plates have the best comprehensive properties, with sufficient strength, excellent plasticity and low hardness, which is one of the reasons why they are widely used. Austenitic stainless steel is similar to most other metal materials, its tensile strength, yield strength and hardness increase with the decrease of temperature; plasticity decreases with the decrease of temperature. Its tensile strength increases uniformly in the temperature range of 15~80°C. More importantly: as the temperature decreases, the impact toughness of stainless steel screws decreases slowly, and there is no brittle transition temperature. Therefore, stainless steel can maintain sufficient plasticity and toughness at low temperature.
door cover structure with hidden screws includes a glass panel, an inner door cover, a computer board and a sealing strip, an adhesive bracket is adhered to the back of the glass panel, the inner door cover is fixedly connected with the adhesive bracket through screws, and the computer board is arranged on the glass panel. In the cavity formed by the panel and the inner door cover, the inner door cover is provided with a sealing slot, the sealing strip is embedded in the sealing slot, and the bottom of the sealing slot is provided with a mounting hole for the screw to pass through, and the glue The bracket is provided with a fixing hole matched with a screw thread, and the screw passes through the installation hole of the inner door cover and is threadedly connected with the fixing hole of the adhesive bracket, so as to fixedly connect the inner door cover and the glass panel. The screw is hidden in the sealing groove of the door cover, and is sealed with water through the sealing strip. The appearance is beautiful, easy to disassemble and assemble, and it can effectively protect the screw from rust.
The circlip lifting and tightening mechanism includes a lifting mechanism and a tightening mechanism; the lifting mechanism includes a lifting cylinder and a ball screw; the output shaft of the lifting cylinder is connected with the ball screw; the ball screw drives the tightening mechanism to achieve up and down move; the tightening mechanism includes a tightening motor, and the output shaft of the tightening motor drives a pinion sleeved on the output shaft to rotate; the pinion drives the largest gear meshed with it to rotate, and the largest gear is driven by The second largest gear meshed with it rotates; the diameter of the first largest gear is the same as that of the second largest gear; the lower ends of the rotating shafts of the first largest gear and the second largest gear are equipped with rotating discs, and each rotating disc is fixedly installed A probe; two probes can be inserted into the two holes of the circlip at the same time, and the circlip can be tightened or loosened as the motor rotates.
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