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Winches
A winch is a mechanical device that is used to pull in (wind up) or let out (wind out) or otherwise adjust the tension of a rope or wire rope (also called "cable" or "wire cable"). In its simplest form, it consists of a spool (or drum) attached to a hand crank. Traditionally, winches on ships accumulated wire or rope on the drum; those that do not accumulate, and instead pass on the wire/rope (see yacht photo above), are called capstans. Despite this, sailboat capstans are most often referred to as winches. Winches are the basis of such machines as tow trucks, steam shovels and elevators. More complex designs have gear assemblies and can be powered by electric, hydraulic, pneumatic or internal combustion drives. It might include a solenoid brake and/or a mechanical brake or ratchet and pawl which prevents it unwinding unless the pawl is retracted. The rope may be stored on the winch. When trimming a line on a sailboat, the crew member turns the winch handle with one hand, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Winch
A winch is a mechanical device that is used to pull in (wind up) or let out (wind out) or otherwise adjust the tension of a rope or wire rope (also called "cable" or "wire cable"). In its simplest form, it consists of a spool (or drum) attached to a hand crank. Traditionally, winches on ships accumulated wire or rope on the drum; those that do not accumulate, and instead pass on the wire/rope (see yacht photo above), are called capstans. Despite this, sailboat capstans are most often referred to as winches. Winches are the basis of such machines as tow trucks, steam shovels and elevators. More complex designs have gear assemblies and can be powered by electric, hydraulic, pneumatic or internal combustion drives. It might include a solenoid brake and/or a Mechanical brake stretch wrapper, mechanical brake or ratchet (device), ratchet and pawl which prevents it unwinding unless the pawl is retracted. The rope may be stored on the winch. When trimming a line on a sailboat, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steam Shovel
A steam shovel is a large steam-powered excavating machine designed for lifting and moving material such as rock and soil. It is the earliest type of power shovel or excavator. Steam shovels played a major role in public works in the 19th and early 20th century, being key to the construction of railroads and the Panama Canal. The development of simpler, cheaper diesel-powered shovels caused steam shovels to fall out of favor in the 1930s. History Origins and development Grimshaw of Boulton & Watt devised the first steam-powered excavator in 1796. In 1833 William Brunton patented another steam-powered excavator which he provided further details on in 1836. The steam shovel was invented by William Otis, who received a patent for his design in 1839. The first machines were known as 'partial-swing', since the boom could not rotate through 360 degrees. They were built on a railway chassis, on which the boiler and movement engines were mounted. The shovel arm and driving engines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wire Rope
Steel wire rope (right hand lang lay) Wire rope is several strands of metal wire twisted into a helix forming a composite ''rope'', in a pattern known as ''laid rope''. Larger diameter wire rope consists of multiple strands of such laid rope in a pattern known as ''cable laid''. In stricter senses, the term ''wire rope'' refers to a diameter larger than , with smaller gauges designated cable or cords. Initially wrought iron wires were used, but today steel is the main material used for wire ropes. Historically, wire rope evolved from wrought iron chains, which had a record of mechanical failure. While flaws in chain links or solid steel bars can lead to catastrophic failure, flaws in the wires making up a steel cable are less critical as the other wires easily take up the load. While friction between the individual wires and strands causes wear over the life of the rope, it also helps to compensate for minor failures in the short run. Wire ropes were developed starting with min ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capstan (nautical)
A capstan is a vertical- axled rotating machine developed for use on sailing ships to multiply the pulling force of seamen when hauling ropes, cables, and hawsers. The principle is similar to that of the windlass, which has a horizontal axle. History The word, connected with the Old French ''capestan'' or ''cabestan(t)'', from Old Provençal ''cabestan'', from ''capestre'' "pulley cord," from Latin ''capistrum'', -a halter, from ''capere'', to take hold of, seems to have come into English (14th century) from Portuguese or Spanish shipmen at the time of the Crusades. Both device and word are considered Spanish inventions. Early form In its earliest form, the capstan consisted of a timber mounted vertically through a vessel's structure which was free to rotate. Levers, known as bars, were inserted through holes at the top of the timber and used to turn the capstan. A rope wrapped several turns around the drum was thus hauled upon. A rudimentary ratchet was provided to hold t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crank (mechanism)
A crank is an arm attached at a right angle to a rotating shaft by which circular motion is imparted to or received from the shaft. When combined with a connecting rod, it can be used to convert circular motion into reciprocating motion, or vice versa. The arm may be a bent portion of the shaft, or a separate arm or disk attached to it. Attached to the end of the crank by a pivot is a rod, usually called a connecting rod (conrod). The term often refers to a human-powered crank which is used to manually turn an axle, as in a bicycle crankset or a brace and bit drill. In this case a person's arm or leg serves as the connecting rod, applying reciprocating force to the crank. There is usually a bar perpendicular to the other end of the arm, often with a freely rotatable handle or pedal attached. Examples Familiar examples include: Hand-powered cranks * Spinning Wheel * Mechanical pencil sharpener * Fishing reel and other reels for cables, wires, ropes, etc. *Starting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pawl
A pawl is a movable lever that engages a fixed component to either prevent movement in one direction or restrain it altogether. As such, it is a type of latch and can also be considered a type of dog. It typically consists of a spring-loaded lever that engages a mating component at a steep enough angle to restrain it. Pawls are often tapered, being widened at their pivot for anchoring and narrow at their tip. Applications ;Anchor windlass: A pawl is used in an anchor windlass to prevent a free-spooling chain by grabbing and snubbing an individual link. Similar mechanisms include a Devil's claw, or a claw and dog. ;Ratchet: A pawl is used in combination with a ratchet gear in socket wrenches, bicycle freehubs, winches, and many other applications. ;Ladder: Dogs (in the form of pawls) are used on extension ladders to temporarily anchor their sections to one-another. ;Table saw: Pawls are used on table saws to prevent a workpiece being sawn from kicking back. ;Transmission: A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Journal Of Hellenic Studies
''The Journal of Hellenic Studies'' is an annual peer-reviewed academic journal covering research in Hellenic studies. It also publishes reviews of recent books of importance to Hellenic studies. It was established in 1880 and is published by Cambridge University Press on behalf of the Society for the Promotion of Hellenic Studies. The editor-in-chief is Lin Foxhall (University of Liverpool). Editors The following persons have been editors-in-chief of the journal: *Percy Gardner Percy Gardner, (24 November 184617 July 1937) was an English classical archaeologist and numismatist. He was Disney Professor of Archaeology at the University of Cambridge from 1879 to 1887. He was Lincoln Professor of Classical Archaeology and ..., 1879-1895 * Ernest Arthur Gardner, 1897-1932 *Roger Brock, 2011-2016 *Douglas Cairns, 2016-2021 References External links * * Hathi Trust''Journal of Hellenic Studies'' 1880- Classics journals Publications established in 1880 English-language jou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanics (Aristotle)
''Mechanics'' ( el, Μηχανικά; la, Mechanica), also called ''Mechanical Problems'' or ''Questions of Mechanics'', is a text traditionally attributed to Aristotle, but generally regarded as spurious. Thomas Winter has suggested that the author was Archytas. However, Michael Coxhead says that it is only possible to conclude that the author was one of the Peripatetics. During the Renaissance, an edition of this work was published by Francesco Maurolico. A Latin translation was made by Vettor Fausto, dedicated to Giovanni Badoer Giovanni Badoer or Zuan Badoer ( – January 1535) was a poet, politician and diplomat of the Republic of Venice. Badoer was the resident ambassador in Spain (1498–1499; 1512–1514), Naples (1500–1501), Hungary (1501–1503), the Holy See (15 ... in 1517. See also * Aristotle's wheel paradox Notes External links * Pseudo-Aristotle, ''Mechanica''- Greek text and English translation * Works by Aristotle Ancient Greek technology< ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aristotle
Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of philosophy within the Lyceum and the wider Aristotelian tradition. His writings cover many subjects including physics, biology, zoology, metaphysics, logic, ethics, aesthetics, poetry, theatre, music, rhetoric, psychology, linguistics, economics, politics, meteorology, geology, and government. Aristotle provided a complex synthesis of the various philosophies existing prior to him. It was above all from his teachings that the West inherited its intellectual lexicon, as well as problems and methods of inquiry. As a result, his philosophy has exerted a unique influence on almost every form of knowledge in the West and it continues to be a subject of contemporary philosophical discussion. Little is known about his life. Aristotle was born in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hoist (device)
A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fiber or wire rope as its lifting medium. The most familiar form is an elevator, the car of which is raised and lowered by a hoist mechanism. Most hoists couple to their loads using a lifting hook. Today, there are a few governing bodies for the North American overhead hoist industry which include the Hoist Manufactures Institute, ASME, and the Occupational Safety and Health Administration. HMI is a product counsel of the Material Handling Industry of America consisting of hoist manufacturers promoting safe use of their products. Types The word “hoist” is used to describe many different types of equipment that lift and lower loads. For example, many people use “hoist” to describe an elevator. The information contained here pertains specially to overhead, cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Assyria
Assyria (Neo-Assyrian cuneiform: , romanized: ''māt Aššur''; syc, ܐܬܘܪ, ʾāthor) was a major ancient Mesopotamian civilization which existed as a city-state at times controlling regional territories in the indigenous lands of the Assyrians from the 21st century BC to the 14th century BC, then to a territorial state, and eventually an empire from the 14th century BC to the 7th century BC. Spanning from the early Bronze Age to the late Iron Age, modern historians typically divide ancient Assyrian history into the Early Assyrian ( 2600–2025 BC), Old Assyrian ( 2025–1364 BC), Middle Assyrian ( 1363–912 BC), Neo-Assyrian (911–609 BC) and post-imperial (609 BC– AD 630) periods, based on political events and gradual changes in language. Assur, the first Assyrian capital, was founded 2600 BC but there is no evidence yet discovered that the city was independent until the collapse of the Third Dynasty of Ur in the 21st century BC, when a line of independent kin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hellespont
The Dardanelles (; tr, Çanakkale Boğazı, lit=Strait of Çanakkale, el, Δαρδανέλλια, translit=Dardanéllia), also known as the Strait of Gallipoli from the Gallipoli peninsula or from Classical Antiquity as the Hellespont (; grc-x-classical, Ἑλλήσποντος, translit=Hellēspontos, lit=Sea of Helle), is a narrow, natural strait and internationally significant waterway in northwestern Turkey that forms part of the continental boundary between Asia and Europe and separates Asian Turkey from European Turkey. Together with the Bosporus, the Dardanelles forms the Turkish Straits. One of the world's narrowest straits used for international navigation, the Dardanelles connects the Sea of Marmara with the Aegean and Mediterranean seas while also allowing passage to the Black Sea by extension via the Bosporus. The Dardanelles is long and wide. It has an average depth of with a maximum depth of at its narrowest point abreast the city of Çanakkale. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
