Service HotlineFan rivets are specially designed for manual installation. They can be pulled in through the holes of the panel or the bottom frame. They are made of elastomer material with good toughness and can be installed quickly even in interference assembly. The design is clever and has elastic function. It is not easy to slide out after being pulled in with the corresponding aperture. The fan rivets are mainly used in the fixing of electronic computer case fans, heat sinks and chips, with anti-vibration and noise reduction.
According to the development and evolution process of self-tapping screws, we believe that the main types of self-tapping screws are as follows: 1. Common self-tapping screw threads are self-tapping threads, also known as wide thread. The surface is mostly electroplated. 2. Self-cutting and self-tapping screws are called scraping ends of self-tapping screws in my country's standard. The threads are self-tapping threads or machine threads, and the cross grooves are also H type. There are several types of self-cutting self-tapping screws: cross recessed pan head self-cutting self-tapping screws, cross recessed countersunk head self-cutting self-tapping screws. Cross recessed countersunk head self-cutting self-tapping screws, hexagon head self-cutting self-tapping screws. 3. Self-extrusion and self-tapping screws (self-tapping locking screws) The threads of self-extrusion and self-tapping screws are generally machine threads, and self-tapping threads are rarely used. In the wrenching method, in order to ensure the use of high-speed automatic assembly wrenches, slotting is generally not recommended. The cross section of the screw of the self-extrusion self-tapping screw is triangular. So it is also called triangular thread screw. 4. Self-drilling and self-tapping screws (self-drilling screws) The threads of self-drilling and self-tapping screws are self-tapping threads according to Chinese, German and international standards. In the American ASME and SAE standards, the BSD self-drilling self-tapping screws are self-tapping threads, and the CSD self-drilling self-tapping screws are machine threads. Self-drilling self-tapping screws are not recommended for slotted and normal hex head. 5. Metal driving screws (metal tapping screws) The metal driving screws have multiple threads and special threads with a certain helix angle. Only the American standard has metal drive screws, and there are no Chinese and German standards. 6. Wallboard self-tapping screws (dry wall screws) Wallboard white tapping screws are special threads with horn head, cross groove (H type) and 60° profile angle, and the surface is mostly phosphate treatment (phosphating). 7. The cross groove of the fiberboard nail is Z-shaped, and the surface treatment is mostly electroplating. There are several types of fiberboard nails: countersunk head, double countersunk head fiberboard nails, pan head, pan head flange (with pad) fiberboard nails, semi-countersunk head, semi-countersunk head flange (with cushion) fiberboard nails. 8. Combination self-tapping screws Ordinary self-tapping screws, self-cutting self-tapping screws, self-drilling self-tapping screws, etc., and flat washers, elastic washers (including spring washers, elastic locking washers, etc.). 9. Others Self-tapping screw types High and low thread double lead self-tapping screws, coarse and fine thread (different pitch) thread self-tapping screws, threads coated with sealing material (fall resistance) self-tapping screws, various composite groove self-tapping screws, Other special self-tapping screws, etc. In short, there are many types of self-tapping screws. With the development of production, the advancement of technology, new materials, new structures, and new thread forms, new self-tapping screw products will continue to appear.
In the prior art, the independent pocketed spring is to encapsulate the springs in bags independently, connect each independent pocketed spring side by side, and then cover it with a large non-woven fabric to form a Spring cushions. This spring mat structure has many disadvantages: 1. Uneven force and low hardness; 2. Easy to deform, pit, low flatness and unsightly; 3. The spring directly contacts the non-woven fabric, causing wear and tear, and the life of the spring mat relatively short.
Usually, the forming of the bolt head adopts cold heading plastic processing. Compared with the cutting process, the metal fiber (metal wire) is continuous along the shape of the product, and there is no cut in the middle, thus improving the strength of the product, especially the mechanical properties. The cold heading forming process includes cutting and forming, single-station single-click, double-click cold heading and multi-station automatic cold heading. An automatic cold heading machine performs multi-station processes such as stamping, heading forging, extrusion and diameter reduction in several forming dies. The processing characteristics of the original blank used by the single-station or multi-station automatic cold heading machine are determined by the size of the bar with a length of 5-6 meters or the wire rod with a weight of 1900-2000KG, that is, the characteristics of the processing technology. The point is that cold heading does not use pre-cut single blanks, but uses the automatic cold heading machine itself to cut and upset (if necessary) blanks from bars and wire rods. Before extruding the cavity, the blank must be shaped. A blank that meets the technological requirements can be obtained by shaping. Before upsetting, reducing and positive extrusion, the blank does not need to be shaped. After the blank is cut, it is sent to the upsetting and shaping station. This station can improve the quality of the blank, reduce the forming force of the next station by 15-17%, and prolong the life of the die, and the bolts can be made with multiple diameter reductions. The precision that can be achieved by cold heading is also related to the selection of the forming method and the procedure used. In addition, it also depends on the structural characteristics of the equipment used, the process characteristics and its state, the precision of the tool and die, the life and the degree of wear. For high-alloy steel used in cold heading forming and extrusion, the roughness of the working surface of the cemented carbide mold should not be greater than Ra=0.2um. When the roughness of the working surface of this type of mold reaches Ra=0.025-0.050um, it has the highest life.
As the preferred embodiment of the above-mentioned embodiment, the motor 41 is provided with a thruster 46 that moves the cutting wheel 42 toward the conveying device 3. When the screw needs to be slotted, the thruster 46 generates a thrust toward the screw, and the motor 41 generates a thrust in the direction of the screw. Under the action, the groove is moved along the track 47 toward the screw. The other end of the motor 41 is provided with a bearing 45, and the output end of the motor is provided with a special-shaped wheel 44. The special-shaped wheel 44 is geared to the bearing 45. The wheel 42 is close to or away from the conveying device 3. When the grooving is completed, the special-shaped wheel 44 rotates and drives the bearing 45 to generate the opposite force from the above-mentioned thrust, so that the motor 41 moves back to the initial position along the track 48.
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