A backpack—also called bookbag, knapsack, rucksack, rucksac, pack, sackpack or backsack—is, in its simplest form, a cloth sack carried on one’s back and secured with two straps that go over the shoulders, but there can be variations to this basic design.
Backpacks are commonly used by hikers and students, and are often preferred to handbags for carrying heavy loads or carrying any sort of equipment, because of the limited capacity to carry heavy weights for long periods of time in the hands.
Large backpacks, used to carry loads over 10 kilograms (22 lb), as well as smaller sports backpacks (e.g. running, cycling, hiking and hydration), usually offload the largest part (up to about 90%) of their weight onto padded hip belts, leaving the shoulder straps mainly for stabilising the load. This improves the potential to carry heavy loads, as the hips are stronger than the shoulders, and also increases agility and balance, since the load rides nearer the wearer’s own center of mass.
Typology
There are different models of backpacks, depending on the specific objective: climbing, hiking, traveling, military and baby carriers, to name a few. There are also so-called hydration backpacks, manufactured to carry a water tank inside, and that have a hose that passes over the shoulder. If they are classified by their capacity, they can be divided into three large groups:
Up to 40 liters: These are used for activities of a day or for attack.
From 40 to 65 liters: Its most common use is for activities in which at least one night will be spent outside, since it is necessary to carry the sack, bivouac holster, stove, etc.
More than 65 liters: This type of backpacks is used for activities of several days or to carry portages.
By capacity
The capacity of a backpack is one of its most important parameters. There is no definite classification for the capacity of backpacks, usually the maximum total volume, which can range from several liters (the smallest urban ones) to about 150 liters (the most voluminous “expedition” backpacks), is usually indicated on the sale.
Tourist backpacks usually have a volume of 40-70 liters, which is enough for a trip for several days (up to a week). Smaller backpacks are used by children, as well as in short 1-2 day trips, larger ones for carrying bulk cargo and for long autonomous campaigns.
By design
Soft (without stiffeners).
These include, for example, old Soviet tourist backpacks, including “koloboks” and “Abalakovo”, as well as a large part of simple urban backpacks. They are just a bag with straps, it is possible – with external and internal pockets, partitions, etc. The volume of such backpacks usually does not exceed 50-60 liters. Easy to manufacture, have a small own weight and folded to take up little space. Require skill when stacking things, but even with its presence are relatively inconvenient for cargo transportation.
Rigid (“easel”).
This category includes, mainly, mountaineering and tourist backpacks of a large volume. They are equipped with a rigid suspension system consisting of an aluminum (less often titanium) frame and a cloth belt. This design provides a more comfortable wearing a backpack, carrying some of the weight from the shoulders to the pelvic area. The straps are attached to the frame and actually a bag with a volume of up to 100 liters. Such backpacks are more convenient for carrying cargo than soft, and do not require much art in stacking things. Due to the frame between the backpack and back formed an air layer, which provides ventilation of the back.
The disadvantages of easel backpacks include the rigidity of their frame, which, for example, can cause serious injuries in the fall. They are difficult to lift or lower on a rope on steep slopes and in vertical caves, and the weight of the backpack due to the frame is significantly increased.
Semi-rigid (“anatomical”).
In this category there are backpacks of almost all types and volumes. The base of the semi-rigid backpack is the inner frame, for example, the “hardness plate”, which is a plate of duralumin 2-3 mm thick, bent over the shape of the back, or foam-polyethylene with a thickness of 15 “, inserted into the” back “of the backpack (part of the backpack, facing the human back) 20 mm. Other frame designs are also used, such as tubular light-alloy frames or plastic flaps of various shapes. The frame provides the rigidity of the backpack and the preservation of its shape, regardless of the nature of the load. Because of the features of the form, these backpacks are often called “anatomical”. They have a volume of up to 140 liters (sometimes more, but it becomes inconvenient). They are made of synthetic fabrics, the straps and waist belt, as a rule, are wide enough, soft and elastic.
Some disadvantages of semi-rigid backpacks are their tight fit to the back of the carrier, making ventilation difficult and leading to intense sweating, which under certain conditions can cause hypothermia of the dorsal and lumbar regions. To avoid this, many backpacks are equipped with special ventilated pads with specially formed air channels.
By appointment
Tourist.
For hiking.
Climbing.
For climbing in a mountainous area.
Bicycles.
For traveling by bike, motorcycle.
They can be worn (worn in the usual way) and luggage (“pants”, placed on the trunk);
Military.
For use by servicemen in combat conditions; The marketing names also use the names “tactical” and “assault” backpack (from English “tactical” and “assault”).
The most characteristic distinctive feature (except for such camouflage coloring) is the presence on the backpack of special fasteners (fasteners, cellular fastening system MOLLE, “Velcro”), with which it is possible to attach additional attachments (pouches), and, possibly, attachments for hanging backpack for body armor.
Classification of military backpacks is ambiguous, often allocate “assault” (about 30 liters, for the minimum required in combat), “three-day” (30-50 liters, calculated for independent actions within 1-2 days) and “raid” (for long-term exits over long distances, large volume with a mandatory waist belt).
Free.
For descents on snow slopes on alpine skiing, snowboarding.
Urban.
Small (10-30 l) backpacks for everyday wear of personal belongings, a laptop, a tablet computer, replacing a bag, a briefcase. Such backpacks often have a catchy appearance and are the subject of fashion. Among the city backpacks can be identified several characteristic species:
specialized professional – for tools, for laptops with accessories, for photographic equipment; are distinguished by division into sections and by the presence of elements designed for a specific application, for example, by the presence of a rigid protected compartment for fragile equipment, fixtures for hand tools, fixed inside cases or pockets for small items, and so on;
women’s and children’s – in fact, ladies’ and children’s handbags with straps for wearing on their backs, women are often made of expensive materials with ornaments, children’s – from bright fabrics with images;
educational – school bag, made in the form of a backpack of dense synthetic materials, strong enough and well-shaped, often has a colorful coloring, usually has several capacious outer pockets, and the internal volume is divided into sections with a thoughtful system of laying out textbooks, writing books, writing materials, placing gadgets, etc.
Construction
Manufacture
The sanity, a derivative of the polyamide is the material most widely used today for the construction of bags, since it is provided with an excellent weight and resistance to abrasion and tearing. The most recommended thickness ranges from 500 to 8000 deniers. By means of a finished with coating, resinated or induced, of polyurethane, the waterproofing of the backpacks is achieved, although the seams will always be the preferred waterways to make inroads into the clothes, sack and other things that we carry inside. Some medium and large capacity super lightweight backpacks use fabrics such as Kevlar, fiber with high resistance to abrasion, for its construction.
It is usually preferred to use backpacks, instead of bags to carry heavy loads in long periods of time, because the shoulders support the weight better than the hands. The larger backpacks discharge most of the weight in belts that surround the hips, leaving the bands that go through the shoulders just to stabilize the load. This allows carrying heavy loads because the hips are even stronger than the shoulders and improves agility and balance because the load resides near the center of mass of the human body. In addition, this allows you to discharge the load spine that can damage it.
Suspension system
Suspension system of the backpack consists of one or two shoulder straps and, possibly, a waist belt. Backpacks of up to about 20 liters in volume are usually supplied with shoulder straps only, for backpacks of larger volume, a waist belt is added to them, which makes it possible to better secure the backpack on the back, avoiding moving it while walking, slipping, and carrying part of the load from the shoulders and spine to the lower back. In some, mainly – military backpacks, straps are supplied with quick-release fasteners, which make it possible to quickly drop the backpack from the back. On the chest shoulder straps can have a horizontal strap-strap on the buckle that fixes the straps on the chest and prevents the straps from slipping off their shoulders. On the waist belt and even directly on the straps can additionally be fastened with pouches for objects, which it is desirable to be able to extract without removing the backpack. In some cases, narrow pockets (for example, a mobile phone or a radio station) can be made directly in the straps.
One-shoulder backpacks instead of two shoulder straps have only one shoulder strap and are worn so that the shoulder strap passes diagonally across the chest and abdomen. For ease of putting on and removing the backpack, the strap is made detachable, on a plastic fastener or “velcro”. In order for the satchel not to slip on its side, an additional fixing strap can be used, coming from the free lower corner of the knapsack, with fastening for the main strap, or a waist strap. A one-shoulder backpack can be fitted for carrying either on the right or only on the left shoulder, or allow adjustment to be worn on any shoulder. In one-legged design, they mainly make military and city backpacks. In the first case, this is due to the need to carry arms and firing on the shoulder with the butt of the butt to the shoulder, which the strap of the backpack can interfere with, in the second – with the need to often remove the backpack from the shoulders (for example, in transport). A backpack with one strap is not only easier and quicker to remove, it can be moved without removing, from the back to the side or on the chest, if there is a need to quickly take something, put it or sit down with a backpack in the vehicle chair.
Modern suspension system of the backpack allows relatively comfortable to carry large enough loads (up to 30 kg and more). In terms of the size of the fasteners, most modern backpacks are universal, and their suspension system can be tuned to a man of almost any complexion.
Change in volume
If necessary, the volume of the backpack can be increased or decreased by using additional pockets, filling the tube (neck) or pulling the main section of the backpack with lacing or special compression lines. With the help of additional external belts, some of the load can be attached from the rear, from above, from the side and from below the backpack. Some backpacks are equipped with special grids, which can be removed from the pocket, if necessary, fixed on the outer surface of the rucksack and used for carrying items that have a large volume with a relatively small weight (ball, helmet, curtain, lint, etc.). This same net can be used to dry things and clothes on the move, so as not to place wet objects inside the backpack and not to wet the rest of the bag.
The presence on the outer surfaces of the backpack MOLLE sling allows you to attach standard pouches of various sizes. Manufacturers issue compatible pouches of virtually any volume, from small cases the size of a purse to covers with a volume of 10 or more liters. Having initially a backpack of average capacity (30-50 liters) it is possible, if necessary, to weigh it with an additional volume of another 15-20 and even more liters, which does not exclude an additional external hinge on the belts.
Hydrators support
In the part of backpacks, the possibility of using so-called hydrators (drinking systems) is constructively envisaged. The hydrator is a flat polymer bag from 0.5 to 2-3 liters with a mouth for pouring drinking water and a tube with a mouthpiece through which water can be drunk. In the backpack for the hydrator, a special flat pocket with a fastener is provided, providing a permanent vertical position of the bag, a hole for the discharge of the drinking tube and strapped straps on the straps through which the tube can be passed so that the mouthpiece is next to the head. The hydrator partially replaces the flask with water, allowing you to drink directly on the go, without stopping or taking off your backpack.
Backpack designs
Backpacks in general fall into one of four categories: frameless, external frame, internal frame, and bodypack. A pack frame, when present, serves to support the pack and distribute the weight of its contents across the body more appropriately, by transferring much of the weight to the hips and legs. Most of the weight is therefore taken off the shoulders, reducing the chance of injury from shoulder strap pressure (many backpacks equipped solely with shoulder straps can affect the posture of a person carrying more than 14 kg (30 lbs)), as well as being less restrictive of the upper body range of motion. Most backpacks are capable of being closed with either a buckle mechanism, a zipper, or a dry-bag type closure, though a few models use a drawstring fitted with a cord lock for the main compartment.
A bodypack is a backpack fitted with one or more pockets that are suspended on the wearer’s chest and loaded in such a way that the load in the front and the load in the back are close to equal. The majority of the load in a bodypack is carried by the hips. The ideal load carrying system should not disturb the wearer’s natural posture, balance and maneuverability. The load must be dispersed onto the skeletal structure in an even manner, and should not produce unbalanced forces on the body.
Frameless
The simplest backpack design is a bag attached to a set of shoulder straps. Such packs are used for general transportation of goods, and have variable capacity. The simplest designs consist of one main pocket. This may be combined with webbing or cordage straps, while more sophisticated models add extra pockets, waist straps, chest straps, padded shoulder straps, padded backs, and sometimes reflective materials for added safety at night. These packs are generally produced inexpensively.
Some outdoor packs, particularly those sold for day hikes, ultralight backpacking and mountaineering are sometimes frameless as well.
Sports
Sports and hydration backpacks are smaller with a profile closer to the body, wider straps and can come with water bladders and hip belts for running, cycling or hiking. Running hydration packs are the smallest and lightest, many under 2 litres and most under six litres. Compression straps across the top of one’s body are common as are hip belts. Cycling hydration packs are six to ten litres sitting high on the back. Although daypacks are small averaging ten to thirty litres, all Trekking and Hiking hydration packs are generally the largest and heaviest. Thirty five up to sixty five litres and above are common.
External frame packs
External frame packs were designed to carry heavy loads (>20 kg or 40 lb), giving the wearer more support and protection and better weight distribution than a simple, frameless strapped bag. Wooden pack frames were used for centuries around the world. Ötzi the Iceman may have used one in Copper Age Alpine Italy, though some archaeologists believe the frame found with the body was part of a snowshoe. Such packs are common in military and mountaineering applications; metal versions first appeared in the mid-20th century.
The external frame is typically made from aluminum, other lightweight metal alloy, and recently reinforced synthetic polymers or plastic and is equipped with a system of straps and tautly-stretched netting which prevents contact between the metal frame and user’s back. In addition to comfort, this “stand-off” provides the additional benefit of creating air circulation between the frame and the wearer’s back. For this reason, external frame packs are generally considered to be a “cooler load” than internal frame designs. External frame packs have a fabric “sack” portion which is usually smaller than that of internal frame packs, but have exposed frame portions above and below the sack to accommodate attachment of larger items. In addition, the sack can often be removed entirely, permitting the user to customize the configuration of their load, or to transport a non-conventional load such as a quartered game animal. Military packs are often external frame designs due to their ability to carry loads of different shapes, sizes and weights.
The other type of external frame which recently was proposed, is made from composite plastic which is not flexible like current backpack straps and also it is a kind of material that can be shaped like human spine curvature. In this type of backpack, load directly transfers to the shoulders through the non-flexible straps. This non-flexible structure diminishes the momentum at lumbar region of the back. Strap curvature is shaped close to spine curvature and there are two flexible drawstrings to prevent backpack movement in transverse plane. The straps of this backpack are wide enough to distribute the pressure on shoulders and also a white glass wool layer is added to the internal part of them to absorb dynamic forces, which could be produced through walking. This backpack type is an experimental sample that need further options to be prepared for usage. One of the benefits of backpack with external frame is preventing the spine to incline forward during walking that would be helpful in preventing damage of long term backpack carrying.
Internal frame packs
The internal frame backpack is a recent innovation, invented in 1967 by Greg Lowe, who went on to found Lowe Alpine and Lowepro, companies specializing in backpacks and other forms of carrying bags for various equipment. An internal-frame pack has a large fabric section around an internal frame composed of strips of either aluminum, titanium or plastic, sometimes with additional metal stays to reinforce the frame. A complex series of straps works with the frame to distribute the weight and hold it in place. The internal frame permits the pack to fit closely to the wearer’s back and minimizes shifting of the load, which is desirable when participating in activities that involve upper-body movement such as scrambling over rocky surfaces and skiing. However, the tight fit reduces ventilation, so these type of packs tend to be more sweaty than external frame packs. The internal construction also allows for a large storage compartment; a few lash points (including webbing loops and straps for sleeping bags and other large items) may be present, but as the frame is completely integrated, it is difficult to securely lash larger and heavier items which do not fit inside the compartment to the outside of the 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, the improved internal frame models have largely replaced external frame backpacks for many activities.
Daily use
A daypack is a smaller, frameless backpack that can hold enough contents for a day hike, or a day’s worth of other activities. They are not large enough for average wilderness backpacking that use full-sized sleeping bags and backpacking tents, but may be large enough for ultralight backpacking. Padded or unpadded waist straps may be provided to distribute weight across the body.
In many countries, backpacks are heavily identified with students, and are a primary means of transporting educational materials to and from school. In this context they are sometimes known as bookbags or schoolbags. The purchase of a suitably fashionable, attractive, and useful backpack is a crucial back-to-school ritual for many students.
Typical school backpacks generally lack the rigid frame of an outdoor-style backpack and include only a few pockets in the front in addition to the main storage compartment. While traditionally very simple in design, school backpacks are often made with padded shoulder straps and backs as well as additional reinforcement to hold large numbers of heavy textbooks, as well as safety features such as reflective panels to make the wearer of the pack more visible at night.
Backpacks are sometimes worn as fashion accessories, in which they perform the same function as a purse. Some such backpacks designed specifically for women are no larger than a typical purse, and are generally associated with younger women.
School backpacks
Progressively, backpacks have replaced the wallets in school use, since they distribute the weight on the back of the child. It is recommended that they have two adjustable symmetric strips depending on the height of the child. Both the strips and the part of the backpack that supports the back must be padded to avoid damaging the body of the wearer. The backpack should always be a few inches above the child’s waist. Likewise, you must put on and take off avoiding adopting forced postures that could cause muscle injuries. Some problems that children currently suffer are caused by the bad placement of backpacks, and by the excessive weight that schools demand to transport every day.
Special-purpose backpacks
Some backpacks are specifically designed to carry certain items. Common examples include backpacks for small valuable items such as laptops and cameras; backpacks designed to hold laptop computers in particular generally have a padded compartment to hold the computer and medium-sized pockets and flaps to accommodate accessories such as charger cables and mice. These are especially common in college and university settings. In order to supply these devices with electricity, a few high-end backpacks are equipped with solar panels.
Rolling backpacks are backpacks with wheels on the bottom and an extending handle. Because of their design, rolling backpacks reduce the strain on the user, though the shoulder straps may be used to carry the pack for short distances when the terrain is not suitable for wheels. Rolling backpacks are most commonly used while traveling by airplane or train.
Hydration backpacks are also available. These light daypacks are especially designed to hold water in a special water bladder (also known as reservoir), and their purpose is to allow the carrier constant fluid hydration handsfree, so that the carrier can focus on the mission ahead without having to stop for water breaks.
Professional use
Backpacks are a standard part of the load-bearing equipment of soldiers, especially infantry, in most countries, and military-style packs are regularly available to civilians in military surplus stores. Well-known examples include the United States ALICE field pack and the British Army PLCE rucksack attachment, both of which are widely available to civilian markets both as actual military surplus (new or used) and as replicas. Such packs are often, though not always (e.g. the USMC’s ILBE pack), external-frame packs, with the pack itself lashed or pinned to a metal or plastic carrying frame. For units that are entering combat situations, packs may be loaded heavily and can weigh in excess of 100 lbs. Each soldier may carry extra weapons, ammunition, rations, medical supplies, tents or other shelter material, and extra clothing.
Many police tactical units, as well as players of military-style combat games such as paintball and airsoft, use these military-style tactical backpacks and webbing for storing gear and ammunition. There is also a small but thriving industry devoted to creating historical reproductions of military gear; such companies generally produce period-appropriate uniforms and other gear in addition to backpacks.
Some more recent military/tactical designs, especially the MOLLE and ILBE packs used by the United States armed forces, are covered with webbing loop attachment points for increased carrying capacity.
Recently, at least one brand of backpack has been specially designed for professional cooks and culinary students. This sort of backpack is meant to safely carry knives, cooking tools, and other miscellaneous equipment such as notebooks, towels, and uniforms.
Specialist backpacks are used by fire services for wildfire fighting, as well as by rescue services for Search and Rescue. These backpacks are generally very modular, allowing the pack to be reconfigured to the users wishes and are designed to load around the wearers hips. They may include features such as sections for water bladders and specially designed pouches, such as those used to carry personal fire shelters.
Architecture
Made mainly of canvas, usually nylon or equivalent, the backpack can be stiffened with metal slats often aluminum to stay light, even supported by a rack. A backpack is equipped with padded and adjustable shoulder straps that rest the weight of the bag on the shoulders. The hiking bags have the particularity of offering a second fastener at the level of the lower abdomen, to avoid movement of the bag. Often, to be hooked, a loop of strap is integrated at the top between the two straps. On the sides, at the back and below the main volume are numerous pockets and extensions.
Backpacks for travel
Backpacks are sometimes used as luggage, particularly as carry-on bags for airplane travel.
In addition to their use in outdoors pursuits, backpacks are sometimes used in other sports as well. Hydration packs, sometimes used by athletes and military personnel, carry water (in either a bladder or a rigid bottle) and have a tube connected to them from which the wearer can drink without removing the pack; this feature is also included in some more general-purpose hiking backpacks. Backpacks that carry skateboards have also become more popular in the youth culture.
Source from Wikipedia