A tire or tyre is a ring-shaped component that surrounds a wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide traction on the surface traveled over. Most tires, such as those for automobiles and bicycles, are pneumatically inflated structures, which provide a flexible cushion that absorbs shock as the tire rolls over rough features on the surface. Tires provide a footprint, designed to match the weight of the vehicle with the bearing strength of the surface that it rolls over by providing a bearing pressure that will not deform the surface excessively; the materials of modern pneumatic tires are synthetic rubber, natural rubber and wire, along with carbon black and other chemical compounds. They consist of a body; the tread provides traction. Before rubber was developed, the first versions of tires were bands of metal fitted around wooden wheels to prevent wear and tear. Early rubber tires were solid. Pneumatic tires are used on many types of vehicles, including cars, motorcycles, trucks, heavy equipment, aircraft.
Metal tires are still used on locomotives and railcars, solid rubber tires are still used in various non-automotive applications, such as some casters, carts and wheelbarrows. The word tire is a short form of attire, from the idea; the spelling tyre does not appear until the 1840s when the English began shrink fitting railway car wheels with malleable iron. Traditional publishers continued using tire; the Times newspaper in Britain was still using tire as late as 1905. The spelling tyre began to be used in the 19th century for pneumatic tires in the UK; the 1911 edition of the Encyclopædia Britannica states that "he spelling'tyre' is not now accepted by the best English authorities, is unrecognized in the US", while Fowler's Modern English Usage of 1926 says that "there is nothing to be said for'tyre', etymologically wrong, as well as needlessly divergent from our own older & the present American usage". However, over the course of the 20th century, tyre became established as the standard British spelling.
The earliest tires were bands of leather iron placed on wooden wheels used on carts and wagons. A skilled worker, known as a wheelwright, would cause the tire to expand by heating it in a forge fire, place it over the wheel and quench it, causing the metal to contract back to its original size so that it fit on the wheel; the first patent for what appears to be a standard pneumatic tire appeared in 1847 lodged by the Scottish inventor Robert William Thomson. However, this never went into production; the first practical pneumatic tire was made in 1888 on May Street, Belfast, by Scots-born John Boyd Dunlop, owner of one of Ireland's most prosperous veterinary practices. It was an effort to prevent the headaches of his 10-year-old son Johnnie, while riding his tricycle on rough pavements, his doctor, John Sir John Fagan, had prescribed cycling as an exercise for the boy, was a regular visitor. Fagan participated in designing the first pneumatic tires. Cyclist Willie Hume demonstrated the supremacy of Dunlop's tires in 1889, winning the tire's first-ever races in Ireland and England.
In Dunlop's tire patent specification dated 31 October 1888, his interest is only in its use in cycles and light vehicles. In September 1890, he was made aware of an earlier development but the company kept the information to itself. In 1892, Dunlop's patent was declared invalid because of prior art by forgotten fellow Scot Robert William Thomson of London, although Dunlop is credited with "realizing rubber could withstand the wear and tear of being a tire while retaining its resilience". John Boyd Dunlop and Harvey du Cros together worked through the ensuing considerable difficulties, they employed inventor Charles Kingston Welch and acquired other rights and patents which allowed them some limited protection of their Pneumatic Tyre business's position. Pneumatic Tyre would become Dunlop Tyres; the development of this technology hinged on myriad engineering advances, including the vulcanization of natural rubber using sulfur, as well as by the development of the "clincher" rim for holding the tire in place laterally on the wheel rim.
Synthetic rubbers were invented in the laboratories of Bayer in the 1920s. In 1946, Michelin developed the radial tire method of construction. Michelin had bought the bankrupt Citroën automobile company in 1934, so it was able to fit this new technology immediately; because of its superiority in handling and fuel economy, use of this technology spread throughout Europe and Asia. In the U. S. the outdated bias-ply tire construction persisted, until the Ford Motor Company adopted radial tires in the early 1970s, following the 1968 article in an influential American magazine, Consumer Reports, highlighting the superiority of radial construction. The US tire industry lost its market share to Japanese and European manufacturers, which bought out US companies. Tires may be classified according to the type of vehicle they serve, they may be distinguished by the load they carry and by their application, e.g. to a motor vehicle, aircraft or bicycle. Light-duty tires for passenger vehicles carry loads in the range of 550 to 1,100 pounds on the drive wheel.
Light-to-medium duty trucks and vans carry loads in the range of 1,100 to 3,300 pounds on the drive wheel. They are differentiated by speed rating for different vehicles, including (starti
On a firearm or other tool, the pistol grip is that portion of the mechanism, held by the hand and orients the hand in a forward, vertical orientation, similar to the position one would take with a conventional pistol. For firearms, the pistol grip is used by the hand that operates the trigger. Rifles and shotguns without pistol grips are referred to as having "straight" or "upland" style stocks; some firearms, such as some versions of the Thompson submachine gun, have a forward pistol grip, used to stabilize the firearm in operation. The pistol grip serves multiple functions such as a magazine housing, bipod, or tool storage. In some firearms, like the Finnish light machine gun Kk 62, the pistol grip is used as a handle to charge the weapon. Pistol grips are a defining feature in United States gun law. A forward pistol grip on a pistol is restricted under the National Firearms Act. Pistol grips which protrude below the weapon and are not integrated with the shoulder stock are regulated in some states and were regulated by the now-expired Federal Assault Weapons Ban.
Tools with pistol grips run the range from hand saws to pneumatic nailers. The word "gun" appears in the name of pistol-gripped tools such as the glue gun, caulking gun and nail gun. A number of tools, like firearms, have a forward pistol grip. Drills and grinders include this feature for added control. One of the reasons the pistol grip style is so common in machinery is because it is possible to ergonomically position the operating controls. For example, on the AR-15 and M16 rifle, a right-handed user's index finger can control the trigger and magazine release, while the thumb can control the safety or fire mode selector switch, all without needing to remove the palm from the grip
The Calles Law, or Law for Reforming the Penal Code, was a statute enacted in Mexico in 1926, under the presidency of Plutarco Elías Calles, to enforce the restrictions against the Catholic Church in Article 130 of the Mexican Constitution of 1917. Article 130 declared that the state are to remain separate. To that end, it required all "churches and religious groupings" to register with the state and placed restrictions on priests and ministers of all religions. Priests and ministers could not hold public office, canvass on behalf of political parties or candidates, or inherit property from persons other than close blood relatives. President Calles applied existing laws regarding the separation of church and state throughout Mexico and added his own legislation. In June 1926, he signed the "Law for Reforming the Penal Code", which became known unofficially as the "Calles Law." This law provided specific penalties for priests and individuals who violated Article 130 of the 1917 Constitution. For example, wearing clerical garb in public was punishable by a fine of 500 pesos (approximately 250 U.
S. dollars at the time, or worth $4,250 in 2010. A priest who criticized the government could be imprisoned for five years; some states enacted further measures in the name of state separation. Chihuahua, for example, enacted a law permitting only a single priest to serve the entire Catholic congregation of the state. To help enforce the law, Calles seized Church property, expelled all foreign priests, closed monasteries and religious schools. One result of the Calles Law was the Cristero War, a popular uprising of Catholic peasants in regions of central Mexico against the federal Mexican government. Between 1926 and 1934, at least 40 priests were killed during the war. Whereas Mexico had some 4,500 Catholic priests prior to the Cristero War, by 1934 only 334 Catholic priests were licensed by the government to serve Mexico's 15 million people. By 1935, 17 states were left with no priest at all. Under President Lázaro Cárdenas, the Calles Law was repealed in 1938