Service HotlineWhen 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.
Rivets for blind holes, including a cap head and a hole post, the cap head is fixed on one end face of the hole post, a tip is formed on the other end face of the hole post, and the end of the hole post close to the cap head is along its side circumference An annular groove is formed concave inward. After the hole column of the blind hole is placed in the blind hole position of the metal piece, the tip of the end face of the hole column is squeezed into the metal material under the end face of the hole column under the action of external force, and the metal material on the side of the hole column is also affected by the hole. The extrusion of the side of the column makes part of the metal material completely squeezed into the annular groove, so that the annular groove is filled more firmly, and at the same time, the tip is squeezed into the metal material, which can double-position the rivet. Therefore, the self-riveting of the rivet is realized. The rivet also has the advantages of simple structure, simple and fast installation, and no cracking caused by impact and other undesirable phenomena.
The process of removing iron oxide plate from cold heading steel wire rod is stripping and dephosphorization. There are two methods: mechanical dephosphorization and chemical pickling. Replacing the chemical pickling process of wire rod with mechanical phosphorus removal not only improves productivity, but also reduces environmental pollution. This phosphorus removal process includes bending method (the round wheel with triangular grooves is commonly used to repeatedly bend the wire rod), spray nine method, etc. The phosphorus removal effect is good, but the residual iron and phosphorus cannot be removed (the removal rate of iron oxide scale is 97%) ), especially when the iron oxide scale is very sticky, therefore, mechanical phosphorus removal is affected by iron scale thickness, structure and stress state. Carbon steel wire rods used for low strength fasteners (less than or equal to 6.8) High-strength bolts (greater than or equal to grade 8.8) use wire rods to remove all iron oxide scales after mechanical dephosphorization, and then go through a chemical pickling process for compound dephosphorization. For low carbon steel wire rods, the iron sheets left by mechanical dephosphorization are likely to cause uneven wear of grain draft. When the grain draft hole adheres to the iron sheet when the wire rod rubs against the external temperature, the surface of the wire rod produces longitudinal grain marks. More than 95% are caused by scratches on the surface of the steel wire during the drawing process. Therefore, the mechanical phosphorus removal method is not suitable for high-speed drawing.
In specific implementation, the axial three-dimensional shape of the nut and the screw head is in the shape of a pentagonal frustum, the elastic surface of the screw is parallel to the center line of the bolt, and the upper contour line is arc-shaped; the screw can be full or partial thread; the top of the screw head The shape is round.
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