Backpack
From Free net encyclopedia
Template:For Image:Rucksack1.jpg A backpack (also knapsack or, especially in the UK, rucksack, haversack, or packsack) is, in its simplest form, a cloth sack carried on one's back and secured with two straps that go over the shoulders and below the armpits.
Backpacks are often preferred to handbags for carrying heavy loads for long periods of time, because the shoulders are better suited for bearing heavy weights for long periods of time than the hands are. However, large backpacks usually offload part of their weight onto padded hip belts. This improves ease of carrying, because the hips are even stronger than the shoulders, and increases agility, because the load rides nearer the person's own center of mass.
Most backpacks are made from soft materials, but the Boblbee company has introduced a popular product line made with hard (monocoque) shells.
Special-purpose backpacks
Image:Canon-Deluxe Backpack-200-EG.jpg
Some backpacks are specifically designed to carry certain items. Common examples include backpacks for small, high-value items such as laptop computers and cameras (see photo). It is also possible to buy "picnic basket" backpacks that come with plastic dishes and utensils, a tablecloth, etc.
Backpacks for backpacking
Template:Reqphoto One common special type of backpack (often just called a 'pack') is designed for backpacking. Packs are more complex than most other backpacks, with many pockets on the outside, and sometimes even a subdivided main compartment. They usually have lash points on the exterior, so that bulky items may be strapped on. Packs typically stand about 3 feet (1 m) tall.
Packs come in two main types. The older type uses a rigid, external frame to support the cloth part of the pack and give it shape. Wooden pack frames have been used for centuries around the world,Template:Citeneeded and metal versions first appeared in the mid-20th century. Modern pack frames are usually made from lightweight aluminium tubes. The frame typically has a system of straps and pads to keep the sack and the frame from contacting the body, with the added benefit of improved ventilation and decreased sweatiness. The fabric part of the pack occupies part of the frame's length, but the frame typically protrudes above and below. These areas of the frame allow bulky items (such tents, sleeping bags, and thermal pads) to be strapped on.
The main compartment is smaller than that of an internal-frame pack, because bulky items (tents, sleeping bags, thermal pads) are strapped to the parts of the frame not occupied by the main compartment itself.
An internal-frame pack has a large cloth part, and a small frame contained entirely inside. This frame consists of strips of either a metal or specially designed polymer that molds to one's back to provide a good fit. Usually a complex series of straps works with the frame to distribute the weight and hold it in place. Internal-frame packs may provide a few lash points, but it is difficult to lash a large, heavy item so that it stays fixed and does not bounce, so most cargo must fit inside. Sleeping bags are a particularly difficult case, as they are very bulky and take up a large part of an internal-frame pack's storage space. Squeezing a sleeping bag in a compression sack helps it fit in an internal-frame pack.
Internal-frame packs originally suffered from smaller load capacity and less comfortable fit during steady walking, but newer models have improved greatly in these respects. In addition, because of their snug fit, they ride better in activities that involve upper-body movement. External-frame models have vanished completely from the British Isles,Template:Citeneeded but in the United States, some manufacturers continue to produce them.
| Comparison of backpack models | |
|---|---|
| External frame | Internal frame |
| Large metal frame to which the pack is secured | Highly reduced semirigid frame in the inside of the pack |
| Good ventilation | Tight fit and less bouncing |
| Large capacity for bulky strap-on items | Roomy internal storage |
| May cost approximately US$80-130 | May cost approximately US$150-250 (or more) |
See also
- Backpacking
- All-purpose Lightweight Individual Carrying Equipment (ALICE)
- MOLLE
- Hydration packca:Motxilla
de:Rucksack es:Mochila (equipaje) nl:Backpack ja:リュックサック pl:Plecak pt:Mochila ru:Рюкзак sv:Ryggsäck