I'd like to make a suggestion on improving the nai

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Make a suggestion on improving nails for wooden cases

different nail forms for wooden cases will not only affect the use performance of wooden cases, but also affect their recycling

take ordinary wooden cases as an example. According to the requirements of gb12464, the connection and assembly method of wooden cases adopts steel nails. There are many deficiencies in the nailed wooden box, such as weak nail holding force, easy to loosen and deform, troublesome nailing, and not conducive to recycling. In the case of small production of wooden cases, the tools needed for nailing are simple, and a hammer is enough. However, for enterprises specializing in the production of wooden cases, especially those holding export wooden case production licenses, we should learn from the advantages of some foreign wood packaging in structural joints, and use special tools to improve the irrationality of the current nailing form of wooden cases in China

the author has been in contact with dozens of wooden cases of equipment imported from the United States. After investigation, manufacturers not only pay attention to the quality of their products, but also pay great attention to the packaging of the products. From the overall appearance, structure to the form of nails, these wooden boxes can be neat, beautiful, firm and practical. According to the different quality and characteristics of the contents in the wooden box, they can better adopt the combination of logs, multi-layer plywood and broken wood plywood of different specifications. The stressed components of the wooden box transporting heavy equipment are fastened with bolts, and the joint of plates adopts cross conical countersunk head wood screws of different specifications (hereinafter referred to as wood screws) according to different thickness. After testing, analysis and comparison, the differences between wood screws and steel nails are as follows:

1 Nail holding force difference. Nailing on the wooden box often causes the wood board to be cracked, especially at the end of the box plate or the stressed component. When the moisture content of wood is too low (less than 10%) or too high (more than 20%), the above phenomena are more likely to occur during or after nailing, which greatly weakens the nail holding force. However, if screws with different specifications and pitches can be selected according to the density of wood, that is, the degree of softness and hardness, the softer ones use screws with larger pitches, and the harder ones use screws with smaller pitches. For the same wood, screw in or drive in two kinds of nails with the same diameter and length. After pulling out the nails, the nail holding force of the screws is about 3 times that of the steel nails. The larger the screw pitch, the stronger the nail holding force, and the greater the difficulty of prying open. Adding a specific seal is beneficial to preventing theft

2. Difference in nail quantity. There are more than 240 steel nails per square meter in the current nailing method of ordinary wooden boxes in China, which has such problems as low industry concentration calculated by area. On wooden cases of the same specification, if wood screws are used, the number of nails can be reduced by one third. After the drop test, the degree of damage and deformation is less than that of steel nails, and even there is no obvious damage and deformation

3. There were differences in group disassembly and assembly. First, the shear lag coefficient at the position where the real load is applied to the steel nails mentioned above is far greater than the multiple effects of mutual benefit and win-win in other places, such as land appreciation, revitalizing social funds, increasing government taxes, and enhancing industrial upgrading. In addition, the length of the nails is the plate thickness plus the box guard plus 5 ~ 9mm, the nails are solid, and the nail tips are solid. These requirements are beyond reproach to ensure the strength of the wooden cases, but are detrimental to the unpacking and recycling of the wooden cases, People have to use the method of hard sledding. Second, for heavy large-scale equipment, the equipment is usually fixed on the base first, and then the stressed components and box plates of the surrounding and top cover. For precision instruments and equipment with shockproof requirements, the use of wood screws can avoid the adverse vibration caused by hammering in the process of sealing and unpacking. In the process of assembling and disassembling wood screws, if there is a special electric tool, it will be more convenient

4. Recycling differences. After the wooden box connected by steel nails is forcibly knocked and pried, the wood boards and stress-bearing components are basically broken and incomplete, which makes people feel that recycling is of little significance. In addition, the sharp steel nails on the wood boards are frightening. These directly caused the low recycling rate of old wooden boxes and difficulties in processing and utilization, so that a large number of old wooden packages that could have been recycled were burned and discarded, which not only wasted limited forest resources, but also polluted the environment, and had a negative impact on the whole ecological balance

in a word, based on the consideration of improving the appearance quality and use performance of wooden cases, recycling, so as to make man-made wood (plywood, fiberboard, particleboard, etc.), saving resources and protecting the environment, it is suggested to adopt the joint form of bolts and wood screws based on the importance of environmental protection awareness in the packaging cases of some export products and domestic products with high requirements

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