Medium-sized shelf, belongs to a kind of storage shelf, shelf shelf type. It is distinguished and named according to the carrying capacity of shelves. According to this division principle, medium shelf is between light shelf and heavy shelf, so it is called medium shelf. Usually the shelf load is 150 kg/-500 kg layer (the majority of shelf load is calculated by the load of the layer as a unit).

1. Main Frame and Sub-Frame
Medium-sized shelves are composed of pillars, beams and laminates. An independent group has two pillars. Such shelves are called main shelves. If several groups are assembled into one column, the other groups can share one column with the group in front of them except the first group which needs two columns. Such shelves are called sub-shelves.
If the shelf is to be moved frequently, it is recommended to use the main shelf. The shelves connected by the main rack and the auxiliary rack must follow the main rack.
Main frame: two pillars (one pillar: two pillars plus several transverse stayed cable-stayed).
Beams (two beams on the first floor).
Laminates (Laminates are placed on two beams).
Sub-frame: one column (one column: two columns plus several transverse stayed cable-stayed columns).
Beams (two beams on the first floor).
Laminates (Laminates are placed on two beams).
Different types of shelves have different passes to facilitate the connection of beams.  Nowadays, the commonly used passes in the market are trapezoidal hole, butterfly hole, rhombic hole, bean sprout hole, octagonal hole and so on. Specifically, there is no standard for which pass to be adopted, most of which are adopted by each manufacturer according to their own production process.
For medium-sized shelves, trapezoidal holes and butterfly holes are commonly used in the market. The trapezoidal hole is easy to press and expand for customers. The butterfly hole is beautiful and easy to install. Southern manufacturers also adopt their own unique pass, so customers have to rely on their manufacturers for shelf renovation.
Installation steps
1. Stand up a pillar piece and insert two beams out of the bottom butterfly hole to pay attention to alignment.
2. Set up another column piece and insert the beam in step 1 to pay attention to alignment.
3. According to the above insertion method, insert the rest of the beams into the attention alignment according to the required height.
4. Place the laminates on the P-beam in turn and finish.

2. Classification of Medium Shelf
The standard type of medium-sized shelves has beautiful appearance, wide application range, convenient installation and disassembly, 75mm pitch adjustment, bearing capacity in the range of 100~350; non-standard large-span load bearing, 75mm pitch adjustment appearance novel, bearing capacity in the range of 300~1000. Medium-sized shelves are strong and bearing capacity is large. Medium-sized shelves are widely used in shopping malls, supermarkets, enterprise warehouses and institutions. Usually it is divided into medium A type shelves, medium B type shelves and medium C type shelves. Generally, it can be assembled and disassembled, and the height of the laminates can be adjusted; the load-bearing layer bears 200-800 kg; all metal parts of the shelf are treated with rust prevention, and the appearance is electrostatic sprayed; the medium-sized shelves are suitable for storing goods in large and medium-sized warehouses. In practical application, there are type A shelf and type B shelf.
Medium Type A Shelf
No bolt design, easy installation, reliable structure. The use of steel laminates, columns, beams, the entire shelf does not use bolt connection, easy installation and disassembly. The main and secondary connection forms are adopted, and the stability is strong.
Medium A shelf features:
Easy to install, bolt connection, main and secondary connection, with strong stability.
The top, bottom, frame connecting rods, column trays, chips and plug-ins of medium-sized shelves are all fixed with pins and easy to operate.
The maximum load is 300 kg/layer under the relative length of bearing strength. The laminates can be adjusted up and down freely according to 50mm spacing.
The surface of shelf is rusted and sprayed.
Surface color can be selected according to customers, the overall shelf is beautiful, generous and durable.
The specifications for column A are: configuration files for 55 * 5.5 * 1.5 mm special rack.
High quality steel rolling mill is used for automatic punching and leveling, and cut off according to the height specified by customers.
The column pallet connecting rod is formed by bending and stamping of high quality cold plate.
High quality cold plate (SPCC) is used in the plate layer, which is divided into strips, flattened, bended and welded.
No bolt connection, simple assembly and disassembly, beautiful appearance, and can assemble multi-storey frame.
Medium B shelf
The cooling plate Q235 steel ((SPCC)) is used to produce high quality steel. The frame form of beams and columns with sockets and handlebars is used. Applicable to man-made delivery. B-type medium shelves are used in various industries, low cost, safety, reliability, assembly and disassembly is very simple. It can be used alone or in combination with main and auxiliary shelves.
Medium B shelf features:
Medium shelf type B is used in various industries with low cost, safety and reliability. Assembly and disassembly are very simple. It can be assembled with main and auxiliary shelves or used separately.
Medium shelf type B-pillar and diagonal brace are connected by bolts. Columns and P-shaped steel silent beam plugs and sockets form shelf frame and safety pin fixed. The structure is simple and reliable.
Each floor of the shelf can be adjusted by 50 steps.
Medium B shelves are usually no more than 3 meters high and are built on multi-storey shelves.
Medium B shelf column specifications are: 55 * 2.0 mm special shelf mast configuration file.
High quality steel mill is used to punch automatically, according to the height and cut-off specified by customers.
The beam is cold rolled P-shape with specifications of 50 x 30 x 40, 64 and 80 (50).

3. Characteristics of Medium Shelf
1. Full-assembled structure, optional combination, convenient installation and disassembly.
2. The pillars are assembled structure. The steel buckle and insert connection is used between the beams and the pillars, and the safety key is set to lock them to prevent them from falling off.
3. Optimizing the cross-section of shelf materials, choosing a variety of pipes to improve the bearing capacity.
4. The column is equipped with adjusting hole spacing every 60 mm, which can be adjusted arbitrarily according to the height of the goods.
5. Separation bracing can be used to strengthen the connection between adjacent back-to-back columns. The bottom of the column can be used with ground nails to improve safety and reliability.
6. Suitable for general manual or stacker delivery, and large storage enterprises to use.

Introduction
The total load of unit shelf is not more than 2500 KG between 100-shy and 500 KG.  Unit shelf span is usually not
More than 2.6m, less than 1m in depth, and generally less than 3m in height. If the unit shelf span is less than 2 m, the layer load
Within 500KG, it is usually more appropriate to choose medium shelf shelves without beams; if the unit shelf span is more than 2m, then 1.
Generally, only beam shelf shelves can be selected. Medium-sized girderless shelves have adjustable spacing compared with medium-sized girder shelves.
Larger, more stable, beautiful, better coordination with the environment, more suitable for some warehouses with high cleanliness requirements; medium-sized beam
Shelf shelves are more industrialized and suitable for storing metal structure products. Medium shelf shelves are widely used.
Applicable to all walks of life.
This product has the advantages of convenient combination of structure, less space occupied, easy placement of objects, beautiful appearance, arbitrary combination, convenient installation and disassembly, etc.
The road is extensive. Steel laminates can be adjusted up and down arbitrarily in 50mm units to meet various requirements. Its surface is electrostatic
Powder spraying treatment, anti-corrosion and rust-proof, durable, economical and convenient. Suitable for large, medium and small enterprises, can make better use of empty space
Between. Suitable for clothing, electronics, and other industrial warehouses. Dimensions can be made at will without calibration.

4. Composition of Medium Shelf
Medium-sized shelves are composed of pillars, beams and laminates. An independent group has two pillars. Such shelves are called main shelves. If several groups are assembled into one column, the other groups can share one column with the group in front of them except the first group which needs two columns. Such shelves are called sub-shelves.
If the shelf is to be moved frequently, it is recommended to use the main shelf. The shelves connected by the main rack and the auxiliary rack must follow the main rack.
Main frame: two pillars (one pillar: two pillars plus several transverse stayed cable-stayed).
Beams (two beams on the first floor).
Laminates (Laminates are placed on two beams).
Sub-frame: one column (one column: two columns plus several transverse stayed cable-stayed columns).
Beams (two beams on the first floor).
Laminates (Laminates are placed on two beams).