Backpack is a bag carried on the back. The bag is provided with straps whose purpose is to permit mounting on the back. The backpack in their smaller sizes is as small as a regular school bag.
Backpacks can be divided into four main types:
- Backpacks without frames
- Backpacks with inner frame
- Backpacks with external frame (MES )
- Chair Backpacks
In addition to these main types are special backpacks for example, computers with accessories, photographic equipment, etc. Even some types of bags and suitcases have straps that make them be worn as a backpack.
Backpacks without frames are common defined by digopaul.com as school bags and the like. The advantage of them is that they are comfortable and easy at moderate compaction. Disadvantages include the ventilation along the spine becomes almost non-existent and that they tend to be a shapeless lump of trying to pack a lot into them. In addition, there is a risk that hard objects causing pressure and irritates the back. The latter can to some extent be remedied by packing a piece cut from a mat, or other pliable plastic material, closest to the back.
Backpacks with inner frame today are incomparably most common on the market for medium-sized and slightly larger backpacks. They are closer to the body than duffel bags, such is an advantage for balance, especially when climbing and skiing, while providing better stability and ventilation along the spine than backpacks without frame. A further advantage is that they are not particularly bulky to pack in a narrow space compared to a duffle bag, making them popular with such backpackers. Among the disadvantages are that it is difficult to attach the gasket on the outside of the bag in a satisfactory manner. Therefore, bulky and heavy items such as tents packed inside the bag so a sack with inner frame must be significantly larger than a duffel bag, calculated in liters, for a normal mountain hike packing.
Framed backpack has an external frame of heavy metal, steel or aluminum, but can also be made of wood. Steel is generally used in military applications, while aluminum is often used in civil. Wooden occurs almost only in homemade backpacks. The frame is sometimes called Barmes or just wimp. This was long the most common type of backpack but it has now competed out of bags with inner frame in all areas except the really big expedition backpacks where the frame’s benefits are really needed. However, many are still in use because a strong backpack that is used moderately will not wear out in decades. Not infrequently, the frame is longer than the bag so that there is space to attach additional equipment both above and below the backpack. Since the gasket contacts the frame and not directly against the back is fine to clamp objects of varying shape of the frame. The frame is of course also excellent attachment for straps.
On many models, you can take the fabric sack and use the framework directly for carrying packing on, for example, boxes or cans. Another benefit of the framework is the good ventilation along the spine. Among the disadvantages are that the bags of external frame is more wing than those with internal frame, the frame can be in the way when, for example, skiing or climbing, and that the framework take much space, which can be seen on the train or in the trunk of the car. Frames of aluminum may be damaged by rough handling of baggage in connection with such a flight.
Chair backpacks are less supported, but the frame’s function is mainly for these constitute the score to a more or less complex built chair that can be folded out when taken off his backpack. Such bags are common in hunting, fishing and outdoor life easier and not designed to carry heavy gaskets.
For long walks with heavy burden, backpacks with special hip belt as relief for the shoulders are recommended. A portion of the bag’s weight is supported then by the hips instead of your back and shoulders. A special case of these forms of frames so-called gyro-sacs, whose frames are forward hangers in which the waist belt loosely fastened. The backpack’s suspension point is then moved to my hips. This is very energy-saving, but is perceived by some as wobbly.