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Dog (engineering)
In engineering, a dog is a tool or part of a tool, such as a pawl, that prevents or imparts movement through physical engagement. It may hold another object in place by blocking it, clamping it, or otherwise obstructing its movement. Or it may couple various parts together so that they move in unison – the primary example of this being a flexible drive to mate two shafts in order to transmit torque. Some devices use dog clutches to lock together two spinning components. In a manual transmission, the dog clutches, or "dogs" lock the selected gear to the shaft it rotates on. Unless the dog is engaged, the gear will simply freewheel on the shaft. This word usage is a metaphor derived from the idea of a dog (animal) biting and holding on, the "dog" name derived from the basic idea of how a dog jaw locks on, by the movement of the jaw, or by the presence of many teeth. In engineering the "dog" device has some special engineering work when making it – it is not a simple part to make ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tool
A tool is an Physical object, object that can extend an individual's ability to modify features of the surrounding environment or help them accomplish a particular task. Although many Tool use by animals, animals use simple tools, only human beings, whose use of stone tools dates back hundreds of millennia, have been observed using tools to make other tools. Early human tools, made of such materials as Rock (geology), stone, bone, and wood, were used for the preparation of food, hunting, the manufacture of weapons, and the working of materials to produce clothing and useful Cultural artifact, artifacts and crafts such as pottery, along with the construction of housing, businesses, infrastructure, and transportation. The development of metalworking made additional types of tools possible. Harnessing energy sources, such as Working animal, animal power, wind, or steam, allowed increasingly complex tools to produce an even larger range of items, with the Industrial Revolution markin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulkhead (partition)
A bulkhead is an upright wall within the hull (watercraft), hull of a ship, within the fuselage of an airplane, or a car. Other kinds of partition elements within a ship are deck (ship), decks and deckheads. Etymology The word ''bulki'' meant "cargo" in Old Norse. During the 15th century sailors and builders in Europe realized that walls within a vessel would prevent cargo from shifting during passage. In shipbuilding, any vertical panel was called a head. So walls installed abeam (side-to-side) in a vessel's hull were called "bulkheads". Now, the term bulkhead applies to every vertical panel aboard a ship, except for the hull itself. History Bulkheads were known to the ancient Greeks, who employed bulkheads in triremes to support the back of rams. By the Athenian trireme era (500 BC), the hull was strengthened by enclosing the bow behind the ram, forming a bulkhead compartment. Instead of using bulkheads to protect ships against rams, Greeks preferred to reinforce the hull ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bench Vise
A vise or vice (British English) is a mechanical apparatus used to secure an object to allow work to be performed on it. Vises have two parallel jaws, one fixed and the other movable, threaded in and out by a screw and lever. The jaws are often flat but may have grooves, adapt to the shape of the workpiece or be custom made. A vise grip is not a vise but a pair of lever-actuated locking pliers. Etymology The etymology of ''vise'' can be tracked via Middle English ''vys'' Anglo-French ''vyz'' from Latin ''vitis'' "vine". The tight grip of the mechanical device was likened to that of the twines of the plant. Types Face A face vise is the standard woodworking vise, always securely attached to a workbench flush with its work surface. Its jaws are made of wood or metal, the latter usually faced with wood, called cheeks, to avoid marring the work. The movable jaw may include a retractable dog to hold work against a bench dog. A "quick-release" woodworker's vise employs a split ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hewing
In woodworking, hewing is the process of converting a log from its rounded natural form into lumber (timber) with more or less flat surfaces using primarily an axe. It is an ancient method, and before the advent the sawmills, it was a standard way of squaring up wooden beams for timber framing. Today it is still used occasionally for that purpose by anyone who has logs, needs beams, and cannot or would prefer not to pay for finished lumber. Thus, homesteaders on frugal budgets, for example, may hew their own lumber rather than buy it. Definitions ''Hew'' is a general term meaning to strike or blow with a tool such as an axe or sword; to chop or gash, and is used in warfare, stone and woodcutting, and coal and salt mining in this sense. Hewing wood is to shape the wood with a sharp instrument such as an axe, specifically flattening one or more sides of a log. Methods As an ancient method of timber ''conversion'', different methods of each step in hewing have developed in hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timber Framing
Timber framing () and "post-and-beam" construction are traditional methods of building with heavy Beam (structure), timbers, creating structures using squared-off and carefully fitted and Woodworking joints, joined timbers with joints secured by large wooden pegs. If the Structural system, structural frame of Load-bearing wall, load-bearing timber is left exposed on the exterior of the building it may be referred to as half-timbered, and in many cases the infill between timbers will be used for decorative effect. The country most known for this kind of architecture is Germany, where timber-framed houses are spread all over the country. The method comes from working directly from logs and trees rather than pre-cut Lumber#Dimensional lumber, dimensional lumber. Artisans or framers would gradually assemble a building by hewing logs or trees with broadaxes, adzes, and draw knife, draw knives and by using woodworking tools, such as hand-powered Brace (tool), braces and Auger (dril ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feed Dogs
A feed dog is a movable plate which pulls fabric through a sewing machine in discrete steps between stitches. Action A set of feed dogs typically resembles two or three short, thin metal bars, crosscut with diagonal teeth, which move both front to back and up and down in slots in a sewing machine's needle plate: front to back to advance fabric gripped between the dogs and the presser foot toward the needle, and up and down to recess at the end of their stroke, release the fabric, and remain recessed while returning before emerging again to begin a new one. Name A mechanical dog is named to suggest the jaw or teeth of a dog, the animal, clamped on to an object, refusing to let go. This arrangement is called "drop feed" in reference to the way the dogs drop below the needle plate when returning for the next stroke. Allen B. Wilson invented it during the time period 1850 to 1854,The date of 1850 is given by James Paton in his "Sewing Machines" article in the Encyclopædia Bri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lathe (metal)
In machining, a metal lathe or metalworking lathe is a large class of lathes designed for precisely machining relatively hard materials. They were originally designed to machine metals; however, with the advent of plastics and other materials, and with their inherent versatility, they are used in a wide range of applications, and a broad range of materials. In machining jargon, where the larger context is already understood, they are usually simply called ''lathes'', or else referred to by more-specific subtype names ('' toolroom lathe'', '' turret lathe'', etc.). These rigid machine tools remove material from a rotating workpiece via the (typically linear) movements of various cutting tools, such as tool bits and drill bits. Metal lathes can vary greatly, but the most common design is known as the universal lathe or parallel lathe. Construction The design of lathes can vary greatly depending on the intended application; however, basic features are common to most types. These ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lathe Dog
A lathe () is a machine tool that rotates a workpiece about an axis of rotation to perform various operations such as cutting, sanding, knurling, drilling, Deformation (engineering), deformation, facing (machining), facing, Threading (manufacturing), threading and turning, with tools that are applied to the workpiece to create an object with rotational symmetry, symmetry about that axis. Lathes are used in woodturning, metalworking, metal spinning, thermal spraying, reclamation, and glass-working. Lathes can be used to shape pottery, the best-known design being the Potter's wheel. Most suitably equipped metalworking lathes can also be used to produce most Solid of revolution, solids of revolution, plane surfaces and screw threads or helix, helices. Ornamental lathes can produce three-dimensional solids of incredible complexity. The workpiece is usually held in place by either one or two ''centers'', at least one of which can typically be moved horizontally to accommodate var ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-synchronous Transmission
A non-synchronous transmission, also called a crash gearbox, is a form of manual transmission based on gears that do not use synchronizing mechanisms. They require the driver to manually synchronize the transmission's input speed (engine RPM) and output speed (driveshaft speed). Non-synchronous transmissions are found primarily in various types of industrial machinery; such as tractors and semi-tractors. Non-synchronous manual transmissions are also found on motorcycles, in the form of constant-mesh sequential manual transmissions. Prior to the 1950s and 1960s, most cars used constant-mesh (and also sliding-mesh) but non-synchronous transmissions. History Most early automobiles were rear-engined, using a single-speed transmission and belt-drive to power the rear wheels. In 1891, the French Panhard et Levassor automobile used a three-speed manual transmission and is considered to have set the template for multi-speed manual transmissions in motor vehicles. This transmis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manual Transmission
A manual transmission (MT), also known as manual gearbox, standard transmission (in Canadian English, Canada, British English, the United Kingdom and American English, the United States), or stick shift (in the United States), is a multi-speed motor vehicle Transmission (mechanical device), transmission system where gear changes require the driver to manually select the gears by operating a gear stick and clutch (which is usually a foot pedal for cars or a hand lever for motorcycles). Early automobiles used ''sliding-mesh'' manual transmissions with up to three forward gear ratios. Since the 1950s, ''constant-mesh'' manual transmissions have become increasingly commonplace, and the number of forward ratios has increased to 5-speed and 6-speed manual transmissions for current vehicles. The alternative to a manual transmission is an automatic transmission. Common types of automatic transmissions are the Automatic transmission#Hydraulic automatic transmissions, hydraulic automatic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jerk (physics)
Jerk (also known as jolt) is the rate of change of an object's acceleration over time. It is a vector quantity (having both magnitude and direction). Jerk is most commonly denoted by the symbol and expressed in m/s3 (SI units) or standard gravities per second(''g''0/s). Expressions As a vector, jerk can be expressed as the first time derivative of acceleration, second time derivative of velocity, and third time derivative of position: \mathbf j(t) = \frac = \frac = \frac Where: * is acceleration * is velocity * is position * is time. Third-order differential equations of the form J\left(\overset, \ddot, \dot, x\right) = 0 are sometimes called ''jerk equations''. When converted to an equivalent system of three ordinary first-order non-linear differential equations, jerk equations are the minimal setting for solutions showing chaotic behaviour. This condition generates mathematical interest in ''jerk systems''. Systems involving fourth-order derivatives or higher are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clutch
A clutch is a mechanical device that allows an output shaft to be disconnected from a rotating input shaft. The clutch's input shaft is typically attached to a motor, while the clutch's output shaft is connected to the mechanism that does the work. In a motor vehicle, the clutch acts as a mechanical linkage between the engine and transmission. By disengaging the clutch, the engine speed (RPM) is no longer determined by the speed of the driven wheels. Another example of clutch usage is in electric drills. The clutch's input shaft is driven by a motor and the output shaft is connected to the drill bit (via several intermediate components). The clutch allows the drill bit to either spin at the same speed as the motor (clutch engaged), spin at a lower speed than the motor (clutch slipping) or remain stationary while the motor is spinning (clutch disengaged). Types Dry clutch A ''dry clutch'' uses dry friction to transfer power from the input shaft to the output shaft, f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
