The national standard name of the cross recessed small pan head three combination screw is the cross recessed small pan head screw, the spring washer and the flat washer assembly. The national label is GB/T9074.8-1988. This 1988 refers to the year, that is, this standard is the standard issued by the country in 1988. The specifications of the cross recessed small pan head three combination screws, the company's minimum is M2.5, the shortest is 5mm, the largest is M10, and the longest is 90mm.
When the mechanical components are installed on the concrete foundation, the J-shaped and L-shaped ends of the bolts are embedded in the concrete for use. The tensile capacity of the anchor bolt is the tensile capacity of the round steel itself. The size is equal to the cross-sectional area multiplied by the allowable stress value (Q235B: 140MPa, 16Mn or Q345: 170MPA), which is the allowable tensile capacity at the time of design. The anchor bolts are generally made of Q235 steel, which is smooth and round. Rebar (Q345) is strong, and the thread of the nut is not as easy to be round. For light round anchor bolts, the burial depth is generally 25 times its diameter, and then a 90-degree hook with a length of about 120mm is made. If the bolt diameter is large (such as 45mm) and the buried depth is too deep, a square plate can be welded at the end of the bolt, that is, a large head can be made (but there are certain requirements). The burial depth and hook are all to ensure the friction between the bolt and the foundation, so as not to cause the bolt to be pulled out and damaged.
Screws are often used on objects, such as data storage, to support the objects on a bracket. Since the item will vibrate during operation or when subjected to shock, if the shock is not minimized, the item will be damaged. Therefore, some cushioning elements with cushioning properties are applied to the article. The buffer is fixed to the object by the screw. When the object vibrates, the buffer will reduce the vibration, thereby reducing the damage to the object. However, since the buffer is exposed Therefore, when the object is installed or disassembled, the object is moving relative to the bracket, and the friction between the buffer and the bracket will cause the buffer to move. It is very easy to age, thus greatly reducing its service life. SUMMARY OF THE UTILITY MODEL In view of the above, it is necessary to provide a screw combination that can protect a buffer member with buffer performance to improve its service life. A screw combination includes a screw, an elastic retaining ring and a buffer, the screw includes a nut, a threaded portion and a neck formed between the nut and the threaded portion, the retaining ring It is fixed on the neck of the screw, the buffer is sleeved on the screw, and the screw combination further includes a cover set on the screw, and the cover includes a top and a forming part. In the shielding part of the top, the top is located between the nut and the retaining ring, and is blocked by the nut and the retaining ring so as not to be separated from the screw, and the shielding part covers the The retaining ring and the buffer element are slightly exposed from the shielding part. Compared with the prior art, the screw assembly of Guangdong Yueluo Hardware Industry Co., Ltd. protects the buffer by covering the buffer by the shutter, thereby increasing its service life.
1. The taper of the reaming hole should be 90°. It should be guaranteed that it should be less than 90° rather than greater than 90°. This is a key trick. 2. If the thickness of the sheet metal is less than the thickness of the head of the countersunk head screw, you can replace the screw with a smaller size, or it is better to ream a smaller hole instead of reaming the hole to increase the diameter of the bottom hole and cause the parts to not be pressed tightly. 3. If there are multiple countersunk head screw holes on the part, it should be processed more accurately. Once it is drilled crookedly, it will be ugly to assemble, but as long as the error is not large, it can be tightened completely, because when tightening, if the diameter of the screw is not very large. Large (about no more than 8mm), when there is an error in the hole distance, the screw head will be deformed due to the force when it is tightened or it will be tightened.
The technical solution of Guangdong Yueluo Hardware Industry Co., Ltd. is: Guangdong Yueluo Hardware Industry Co., Ltd. discloses an anti-dropping nut, which includes a lock, a lock plate, a nut body, a lock ring and a lock claw. The lock ring and the nut body When used together, the lock ring is a circular ring, the inner diameter of the lock ring is larger than the inner diameter of the circumscribed circle of the nut body, the outer diameter of the lock ring is smaller than the inner diameter of the lock buckle, the lock disk is an arc-shaped metal plate, and the number of lock disks is greater than or equal to three. One short side end of the lock plate is connected to the nut body, and the other end of the lock plate is connected to the lock pawl, the lock plate is inclined to the outside of the nut body, and the lock catch is arranged on the outer side of the connection end between the lock pawl and the lock plate. On the side, the lock is a concave arc.
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