سهچرخههای رکابی سهچرخههایی هستند که با رکاب زدن و نیروی انسانی (با سامانهای شبیه به دوچرخه) به حرکت درمیآیند. سهچرخهها برای کارهای گوناگونی ساخته شدهاند برای نمونه برای ترابری انسان، ترابری بار، برای گردشگران و تفریح و برخی نیز برای انجام مسابقات بهکار میروند.
نمونههایی از سهچرخههای رکابی:
همانند موتور سیکلتها برخی از سهچرخهها نیز موتوری هستند.
نمونههایی از سهچرخههای موتوری:
سهچرخههای محیط زیستی[ویرایش]
نمونههایی از سهچرخههای محیط زیستی:
Tricycles are used by children and adults. In the United States and Canada, adult-sized tricycles are used by senior adults for recreation, shopping, and exercise. In Asia and Africa, tricycles called pedicabs are used to transport passengers; tricycles are also used to transport freight and make deliveries.
In the Philippines, a tricycle is a for hire, public utility vehicle consisting of a motorcycle and an attached passenger sidecar; it is not to be confused with the trisikad, an unmotorised, three-wheeled pedicabs also found in the country.
A three-wheeled wheelchair was built in 1655 or 1680 by a disabled German man, Stephan Farffler, who wanted to be able to maintain his mobility. Since he was a watch-maker, he was able to create a vehicle that was powered by hand cranks.
In 1789, two French inventors developed a three wheeled vehicle, powered by pedals; They called it the tricycle.
In 1818, British inventor Denis Johnson patented his approach to designing tricycles.[clarification needed] In 1876, James Starley developed the Coventry Lever Tricycle, which used two small wheels on the right side and a large drive wheel on the left side; power was supplied by hand levers. In 1877, Starley developed a new vehicle he called the Coventry Rotary, which was "one of the first rotary chain drive tricycles." Starley's inventions started a tricycling craze in Britain; by 1879, there were " twenty types of tricycles and multi-wheel cycles ... produced in Coventry, England, and by 1884, there were over 120 different models produced by 20 manufacturers." The first front steering tricycle was manufactured by The Leicester Safety Tricycle Company of Leicester, England in 1881 which was brought to the market in 1882 costing £18. They also developed a folding tricycle at the same time.
Tricycles were used by riders who did not feel comfortable on the high wheelers, such as women who wore long, flowing dresses. In the UK, upright tricycles are sometimes referred to as "barrows". Many trike enthusiasts ("trikies") in the UK belong to the Tricycle Association, formed in 1929. They participate in day rides, tours and time trials. Massed start racing of upright tricycles is limited to one or two criteriums such as in Bungay, Suffolk each year.
Human powered tricycles
Tricycles generally are uprights, recumbent delta or tadpole. Conversion sets can alter the design of the tricycle.
Upright resembles a two-wheeled bicycle, traditionally diamond frame, or open frame, but with either two widely spaced wheels at the back (called delta) or two wheels at the front (called tadpole). The rider straddles the frame in both delta and tadpole configurations. Steering is through a handlebar directly connected to the front wheel via a conventional bicycle fork in delta, or via a form of Ackermann steering geometry in the case of the upright tadpole.
Recumbent delta is similar to an upright, with two wheels at the back and one at the front, but has a recumbent layout in which the rider is seated in a chair-like seat. One or both rear wheels can be driven, while the front is used for steering (the usual layout). Steering is either through a linkage, with the handlebars under the seat (USS[clarification needed]) or directly to the front wheel with a large handlebar (OSS[clarification needed]).
Recumbent tadpole or reverse trike, is a recumbent design with two steered wheels at the front and one driven wheel at the back, though one model has the front wheels driven while the rear wheel steers. Steering is either through a single handlebar linked with tie rods to the front wheels' stub axle assemblies (Indirect) or with two handlebars (rather, two half-handlebars) each bolted to a steerer tube, usually through a bicycle-type headset and connected to a stub axle assembly (Direct). A single tie rod connects the left and right axle assemblies.
The tadpole trike is often used by middle-aged or retiree-age former bicyclists who are tired of the associated pains from normal upright bikes. With its extremely low center of gravity, aerodynamic layout and light weight (for trikes), tadpoles are considered the highest performance trikes.
Most Velomobiles are build in a tadpole trike configuraton since a wide front and narrow rear offer superior aerodynamics to a delta trike configuration.
Not all trikes fall into one of these three classes. For example, some early pedal tricycles from the late 19th century used two wheels in tandem on one side and a larger driving wheel on the other.
Another design is an in-line three-wheeled vehicle, with two steered wheels: one at the front and the other in the middle or at the rear. It is not unusual for tricycles to have front and rear wheels of different sizes.
Tricycle conversion sets convert a bicycle to a delta or tadpole upright tricycle. The advantages of a trike conversion set include lower cost compared with new, hand built tricycles and the freedom to choose almost any donor bicycle frame.
Tricycle conversion sets tend to be heavier than a high quality, hand built, sports, touring or racing tricycle. Conversion sets can give the would-be, serious tricyclist a taste of triking before making the final decision to purchase a complete tricycle. Conversion sets can also supplied ready to be brazed onto a lightweight, steel, bicycle frame to form a complete trike. Some trike conversion sets can also be used with recumbent bicycles to form recumbent trikes.
Adult and child model comparison
Another way of categorizing tricycles is by whether they are designed for children or adults; children's tricycles and most adult tricycles made for the recreational market use the upright layout. From a design point of view, the difference between children's and adult tricycles is that whereas children's tricycles are usually direct drive and have no brakes, adult trikes usually have a gear-drive with multiple speeds and front and rear brakes.
Tricycles are typically used by children between the ages of two and four, after which point they usually switch to a bicycle, often with training wheels. Parents choosing a tricycle for their child should ensure that the trike is not too tall and that the seat is too high, and that the wheelbase is wide enough, because if this is not the case, the child may tip over easily. The seat should be stable, which is not always the case with the most inexpensive models. Some trikes have back rests which provide support and a push bar for parents so that the parents can push the child up hills or hold the child back when descending, or in case of the sudden approach of other traffic. For safety many parents make children wear a helmet when riding a trike. Some parents also attach a safety flag to the trike so that the child will be more visible to drivers.
Children's trikes are made of steel frames or plastic. One disadvantage of plastic frames is that they are more likely to tip over than a steel frame if a heavier child is riding. On the plus side, plastic frames will not rust like steel frames if the trike is left out in the rain. Children's tricycles can also be made from bamboo. Bamboo has a tensile strength that is comparable to steel while at the same time being lightweight like a plastic frame. Bamboo can also be used to make an adult bamboo bicycle.
While most children's trikes have direct drive, a small number of models such as the Cheetah have chain drive. Unlike adult bikes, children's trikes do not always have pneumatic tires; instead, some trikes have solid rubber wheels. While this adds to the weight of the tricycle and reduces the shock-absorbing qualities, it eliminates issues with flat tires, punctures, and leaky tubes. Since most trikes are direct drive, the child can slow the trike down by resisting the forward motion of the pedals, as with an adult fixed gear bike. Pull brakes are rarely used on children's trikes, but some "Bigwheel"-style plastic trikes have lever brakes in which an inverted half-moon-shaped brake pad is pressed against the driving surface of the right rear wheel.
Adults may find upright tricycles difficult to ride because of familiarity with the counter-steering required to balance a bicycle, in which the weight of the body is used during turns. The variation in the camber of the road is the principal difficulty to be overcome once basic tricycle handling is mastered. Recumbent trikes are less affected by camber and, depending on track width and riding position, capable of very fast cornering. A few trikes are designed to tilt into the corners much as a bicycle does, and this also renders them more comfortable on cambered roads. They are referred to as tilting three-wheelers (TTWs).
In the case of delta tricycles, the drive is often to just one of the rear wheels, though in some cases both wheels are driven through a differential. A double freewheel, preferably using no-backlash roller clutches, is considered superior. Trikes with a differential often use an internally geared hub as a gearbox in a 'mid drive' system. A jackshaft drive permits either single or two-wheel drive. Tadpoles generally use a bicycle's rear wheel drive and for that reason are usually lighter, cheaper and easier to replace and repair.
Recumbent trikes often brake one wheel with each hand, allowing the rider to brake one side alone to pull the trike in that direction. Some trikes use a geometry (also called center point steering) with the kingpin axis intersecting the ground directly ahead of the tire contact point, producing a normal amount of trail. This arrangement, elsewhere called "zero scrub radius" is used to mitigate the effects of one-sided braking on steering. While zero scrub can reduce steering feel and increase wandering it can also protect novices from spinning out and/or flipping.
Tadpole trikes tend also to use Ackermann steering geometry, perhaps with both front brakes operated by the stronger hand. While the KMX Kart stunt trike with this setup allows the rear brake to be operated separately, letting the rider do "bootlegger turns", the standard setup for most trikes has the front brake for each side operated by each hand. The center-of-mass of most tadpole trikes is close to the front wheels, making the rear brake less useful. The rear brake may instead be connected to a latching brake lever for use as a parking brake when stopped on a hill.
Strengths and weaknesses
Recumbent trikes' strongest suits are stability, comfort, and low drag. Trikes can be used by adults who have problems riding bicycles. As well, trikes are a good choice for elderly riders who are worried about falls. Trikes can ride and climb at very low speed and a kickstand is never needed.
Trikes are always heavier than bikes of the same quality. In fact, the lightest commercially made tadpole trikes, at around 29 lb (13 kg), are easily twice the weight of an upright bicycle of the same cost and quality. Deltas are even heavier. Shortcomings potential tadpole trikers should be aware of center on the low riding position, which makes them difficult to mount (grab handles are often available). Visibility in traffic is much debated. People[who?] who do not ride recumbents often assume they will be hard to see in traffic, but their unusual appearance often draws attention, and frequently promotes safer overtaking. Flags and blinking lights are often used, also, especially in urban areas where the rider wishes to filter past queuing traffic (where the rider is often in drivers' blind spots). Visibility concerns become minimal on bike trails and off-street riding.
An often-noted[by whom?] problem with recumbent trikes, much debated by trikers and recumbent riders of all kinds, is their poor climbing ability: the rider cannot get out of the saddle and stand up on the pedals to climb hills. It is however possible to either 'spin' in a lower gear, or sometimes to use the seat back to provide extra leverage (although as this force is not limited by the riders weight it can result in over stressing the knees). Trikers argue that they make up the time lost going up hills by going much faster on the downhill side because of the low, aerodynamic riding position.
Some tricycles (such as the Christiania and the Pashley load trike) are designed for load carrying. Others are designed for racing or for comfort. Some recumbent tricycles are fully enclosed for all weather use as well as aerodynamic benefits; these are known as velomobiles. Some tricycles, such as the Zigo Leader, are designed to transport children.
Hand and foot trike
With hand and foot trikes, the rider makes a pair of front wheels change directions by shifting the center of weight and moves forward by rotating the rear wheel. The hand and foot trike can be also converted into a manual tricycle designed to be driven with both hands and both feet.[better source needed] There are also new hybrids between a handcycle, a recumbent bike and a tricycle, these bikes make it even possible to cycle with legs despite a spinal cord injury.[better source needed]
Tandem and hand trikes
Recumbent tandem trikes allow two people to ride in a recumbent position with an extra-strong backbone frame to hold the extra weight. Some allow the "captain" (the rider who steers) and "stoker" (the rider who only pedals) to pedal at different speeds. They are often made with couplers so the frames can be broken down into pieces for easier transport. Manufacturers of recumbent trikes include Greenspeed, WhizWheelz and Inspired Cycle Engineering (ICE).
Hand-crank trikes use a hand-operated crank, either as a sole source of power or a double drive with footpower from pedals and hand-power from the hand crank. The hand-power only trikes can be used by individuals who do not have the use of their legs due to a disability or an injury. They are made by companies including Greenspeed, Invacare, Quickie and Druzin.
Urban delivery trikes are designed and constructed for transporting large loads. These trikes include a cargo area consisting of a steel tube carrier, an open or enclosed box, a flat platform, or a large, heavy-duty wire basket. These are usually mounted over one or both wheels, low behind the front wheel, or between parallel wheels at either the front or rear of the vehicle, to keep the center of gravity low. The frame and drivetrain must be constructed to handle loads several times that of an ordinary bicycle; as such, extra low gears may be added. Other specific design considerations include operator visibility and load suspension. Many, but not all, cycles used for the purpose of vending goods such as ice cream cart trikes or hot dog vending trikes are cargo bicycles.
Many freight trikes are of the tadpole configuration, with the cargo box (platform, etc.) mounted between the front wheels. India and China are significant strongholds of the rear-loading "delta" carrier trike. Freight trikes are also designed for indoor use in large warehouses or industrial plants. The advantage of using freight trikes rather than a motor vehicle is that there is no exhaust, which means that the trike can be used inside warehouses. While another option is electric golf cart-style vehicles, freight trikes are human-powered, so they do not have the maintenance required to keep batteries on golf carts charged up.
Common uses include:
Most cycle rickshaws, used for carrying passengers for hire, are tricycles with one steering wheel in the front and two wheels in the back supporting a seating area for one or two passengers. Cycle rickshaws often have a parasol or canopy to protect the passengers from sun and rain. These vehicles are widely used in South Asia and Southeast Asia, where rickshaw driving provides essential employment for recent immigrants from rural areas, generally impoverished men. In the 1990s and first decade of the 21st century, rickshaws have become increasingly popular in big cities in Britain, Europe and the United States, where they provide urban transportation, novelty rides, and serve as an advertising media.
Spidertrike is a recumbent cycle rickshaw that is used in central London and is operated by Eco Chariots. The trike pictured is called the SUV (Sensible Utility Vehicle) and is produced by the company Organic Engines, which operates in Florida in the United States. It is a front wheel drive tricycle, articulated behind the driver seat. The passenger is protected from rain and sun with a canopy. These pedicabs have features like double disc, hydraulic disc brakes and internal hub gears.
A treecycle is a cycle rickshaw that is used in Shanghai and invented by Chris Trees. It has a stainless steel frame and a bamboo body. The bike pictured is the cabriolet version without roof. A notable feature is the children's safety seat as used in cars and the storage compartment below the seat. Other models feature a roof or loading deck. All models are center drive tricycles with Gates carbon belt. Features include Nuvinci invariable hub gears, hydraulic disk brakes on all wheels with park-lock function, LED front- indicator- and brake-lights.
Makers of upright trikes include George Longstaff, Higgins (ceased trading in the 1960s but still held in high regard and many of their machines still exist today), Trykit and Pashley Cycles in the UK. Italian company Di Blasi make a folding upright trike, which folds to a compact 68 x 28 x 62.5 cm. There are also many inexpensive, mass-produced upright trikes available through mass-market retailers. They are generally heavy and of uneven quality, but are suitable for occasional, low-demand riding, especially by those with mobility problems.
Makers of recumbent trikes include KMX; Hase (who make the Kettwiesel delta, improbably named after the British children's programme Catweazle); Inspired Cycle Engineering, who make the Trice range of tadpole trikes; AVD, who build the record holding Burrows Windcheetah or Speedy, a design exhibited in the Metropolitan Museum of Modern Art (MoMA); Australia's Greenspeed, one of the oldest manufacturers; Michigan-based WhizWheelz, which makes 10 models, including a tadpole and a tandem; Big Cat HPV which builds the eight Catrike models in Florida and Sidewinder Cycle which has a front wheel drive system with rear wheel steering builds 3 models all with Electric assist capability located in California.
The largest manufacturer of recumbent trikes is Sun Bicycles who make both tadpole and delta trikes. The deltas are built from designs licensed from Gardner Martin's EasyRacers, the premiere maker of recumbent bicycles. Sun bicycles are factory-made in Taiwan and are among the least expensive trikes of good quality.
Some tricycles are powered with motors, typically gasoline engines. Depending on the design of the vehicle, motorized trikes may be categorized as motorcycles, motor scooters, or simply the three-wheeled counterpart to a motorized or electric bicycle. The main difference between a motorcycle trike and a scooter trike is that motorcycles are sat on in a "saddle"-style seating (as with a horse), with the legs apart, and motorcycles have manual transmissions. Scooters have a "step-through" seating style, in which the driver sits on a more chair-like seat, with the legs together; as well, scooters have automatic transmissions. While laypersons often associate the engine size as a dividing line between motorcycles and scooters, since a typical scooter has a small 50 cc engine, engine size is not one of the dividing lines, because some scooters such as the Burgman have 638 cc engines.
Motorcycles with sidecars are not usually considered tricycles. It can be harder to categorize three-wheeled automobiles. While some early prototype automobiles were steam tricycles, 1930s and 1940s-era three-wheeled cars such as Morgan Motor Company cars are often classified as cars rather than motorcycles.
A motorized tricycle's wheels may be arranged in either configuration: delta or tadpole. A delta trike has one wheel in front and two in back, and the tadpole trike has two wheels in front and one in back. Occasionally, rear wheel steering is used, although this increases the turning circle and can affect handling (the geometry is similar to a regular trike operating in reverse, but with a steering damper added). Thrust SSC used a rear-steer tadpole layout (technically, Thrust SSC was not a tricycle; it had four wheels, two at each end. The rear steering wheels (2) were mounted very close together).
Tadpoles are more stable under braking and more likely to slide instead of roll; front braking hard on a delta requires the vehicle to steer almost straight to avoid tipping. The balance of friction patches and rolling resistance also means that tadpoles tend to oversteer and deltas understeer.
Motor trikes are attractive for those with mobility or balance problems, for carrying multiple passengers on a motorcycle license (since January 2013 in Great Britain a full car license is required for ANY trike), or to avoid helmet use regulations. These machines are generally custom-built and often finished to a very high standard.[according to whom?] A common arrangement is to fit chopper-style ("ape hanger") front forks to a VW Beetle engine and transaxle, popular because it is largely self-contained on a single subframe. Similarly, the engine, transmission and rear wheel may be taken from a large motorcycle as a single unit, and used in the construction of a tadpole trike.
Mass-manufactured motor tricycles include the Piaggio MP3; the Piaggio Ape (Italian for Bee) delivery trike (delta); the Harley-Davidson Tri Glide Ultra Classic; the Bombardier Recreational Products Can-Am Spyder (tadpole); the T-Rex reverse trike; trikes used by municipal authorities in the USA; and, historically, vehicles such as the Scammell Scarab railway dray, a common sight around post-war British railway stations.
Motorized freight trikes
In Asian and Southeast Asian countries, motorized trikes are used as small freight trucks and commercial vehicles. Nicknamed "three-wheelers" or "tuk-tuks" in popular parlance, they are a motorized version of the traditional rickshaw or velotaxi. They have a small three-wheeled cart driven by a person, and is related to the cabin cycle.While they are mostly used as taxis for hire, they are also used for commercial and freight deliveries. They are particularly popular where traffic congestion is a problem in cities like Bangkok, Dhaka, Ahmedabad, Pune, Delhi, Mumbai, Chennai, Hyderabad and Bengaluru,
They usually have a sheet-metal body or open frame that rests on three wheels, a canvas roof with drop-down sides, a small cabin in the front of the vehicle for the driver, an air-cooled scooter version of a two-stroke engine, with handlebar controls instead of a steering wheel. The smaller motorized trikes are used as delivery vehicles for lighter loads. The larger trikes, with more powerful engines, have larger cargo bays, and they can carry freight within a city.
Motorized scooter trikes
Scooters are motor vehicles that can vary significantly in design and capability, but are generally derived from a traditional design combining a step-through frame with front fairings and floor boards, inner fairing storage, small wheels (10" to 16" in diameter), and a rear swingarm-mounted engine suitable for light duty. The classic scooter design features a step-through frame and a flat floorboard for the rider's feet. Most newer scooters use a continuously variable transmission (CVT). While most scooters have two wheels, some scooters are three-wheeled scooter trikes.
Most scooter trikes have two rear wheels which are the drive wheels and a front wheel which is used for steering. Some first decade of the 21st century-era scooter trikes such as the Piaggio MP3 are reverse trikes, with two wheels in front and one in the back. The MP3 leans like a 2-wheeled bike, with the front wheels moving independently in a scissors action.
Motorized stand-up trikes
In the Philippines, motorized tricycles are used as a public utility vehicle and for personal transportation.
Various locally made configurations are used around India. They fall under the category of Jugaad and serve as both passenger and commercial vehicles. The motorized versions are popular because of their low cost as they are put together from salvaged motorcycles and often do not require the operator to have a driving license.