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Hirth Joint
A Hirth joint or Hirth coupling is a type of mechanical connection named after its developeAlbert Hirth It is used to connect two pieces of a shaft together and is characterized by tapered teeth that mesh together on the end faces of each half shaft. Construction Hirth joints consist of radial teeth formed by grooves milled or ground into the end face of a cylindrical shaft. The teeth mesh around a ring, as the torque capacity of teeth increases with their diameter. This ring is arranged to be at the maximal possible diameter for the space available. The centre of a shaft is not toothed, as this would add little torque capacity to the coupling and the increasingly narrow teeth would become impractical to cut. For instance, a shaft of 60 mm diameter can be toothed in a 12 mm wide ring only (inner diameter is 36 mm) without jeopardizing the load-bearing capacity of the shaft. Tapered, symmetrical serrations are used. Profile angles of 60 and 90 degrees are used. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hirth Verzahnungsringe
Hirth Engines GmbH is an engine manufacturer based in Benningen, Germany. It is currently a part of the UMS Aero Group. Hirth began manufacturing aero engines in the 1920s, was taken over by Heinkel in WWII to develop the Heinkel-Hirth jet engines, and today specialises in small two-stroke engines for light aircraft and other applications. History Hellmuth Hirth and Hirth Motoren The company was founded by Hellmuth Hirth as Versuchsbau Hellmuth Hirth. The first commercial engine, the 4-cylinder inverted in-line HM 60, first ran in June 1923 and was sold from the next year. Its quality was extremely high and it formed the foundation of the business.Gunston, Bill (1998). ''World Encyclopaedia of Aero Engines'', 4th Edition. Patrick Stephens Ltd (PSL). The company was renamed Leichtmetall-Werke GmbH, Elektronmetall GmbH and eventually separated from the aero engine manufacturing to form Mahle GmbH as a manufacturer of light alloy engine components, specifically the magnesium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crankshaft
A crankshaft is a mechanical component used in a piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating shaft containing one or more crankpins, that are driven by the pistons via the connecting rods. The crankpins are also called ''rod bearing journals'', and they rotate within the "big end" of the connecting rods. Most modern crankshafts are located in the engine block. They are made from steel or cast iron, using either a forging, casting or machining process. Design The crankshaft located within the engine block, held in place via main bearings which allow the crankshaft to rotate within the block. The up-down motion of each piston is transferred to the crankshaft via connecting rods. A flywheel is often attached to one end of the crankshaft, in order to smoothen the power delivery and reduce vibration. A crankshaft is subjected to enormous stresses, in some cases more than per cylinder. Crankshafts for sing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indexing (motion)
Indexing in reference to motion is moving (or being moved) into a new position or location quickly and easily but also precisely. When indexing a machine part, its new location is known to within a few hundredths of a millimeter (thousandths of an inch), or often even to within a few thousandths of a millimeter (ten-thousandths of an inch), despite the fact that no elaborate measuring or layout was needed to establish that location. In reference to multi-edge cutting inserts, indexing is the process of exposing a new cutting edge for use. Indexing is a necessary kind of motion in many areas of mechanical engineering and machining. An object that indexes, or can be indexed, is said to be indexable. Usually when the word ''indexing'' is used, it refers specifically to rotation. That is, indexing is most often the quick and easy but precise rotation of a machine part through a certain known number of degrees. For example, ''Machinery's Handbook'', 25th edition, in its section on milli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indexing Head
An indexing head, also known as a dividing head or spiral head, is a specialized tool that allows a workpiece to be circularly indexed; that is, easily and precisely rotated to preset angles or circular divisions. Indexing heads are usually used on the tables of milling machines, but may be used on many other machine tools including drill presses, grinders, and boring machines. Common jobs for a dividing head include machining the flutes of a milling cutter, cutting the teeth of a gear, milling curved slots, or drilling a bolt hole circle around the circumference of a part. The tool is similar to a rotary table except that it is designed to be tilted as well as rotated and often allows positive locking at finer gradations of rotation, including through differential indexing. Most adjustable designs allow the head to be tilted from 10° below horizontal to 90° vertical, at which point the head is parallel with the machine table. The workpiece is held in the indexing head in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hex Key
Hex keys of various sizes Socket head screws of various sizes A hex key (also, hex wrench, Allen key and Allen wrench) is a simple driver for bolts or screws that have heads with ''internal'' hexagonal recesses (sockets). Hex keys are formed from a single piece of hard hexagonal steel rod, having blunt ends that fit snugly into similarly-shaped screw sockets. The rods are bent to 90º, forming two arms of unequal length resembling an "L". The tool is usually held and twisted by its long arm, creating a relatively large torque at the tip of the short arm; it can also be held by its short arm to access screws in difficult-to-reach locations and to turn screws faster at the expense of torque. Hex keys are designated with a socket size and are manufactured with tight tolerances. As such, they are commonly sold in kits that include a variety of sizes. Key length typically increases with size, but not necessarily proportionally so. Variants on this design have the short end inse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bicycle Torque Coupling
An S and S Coupling also known as a Bicycle Torque Coupling or BTC is a coupling which enables bicycle frames to be separated into smaller pieces, usually to facilitate packing and transporting. Couplings can be built into the frame by the frame manufacturer when the frame is made or can be added to a frame after it is finished. A special spanner is available for tightening and loosening the couplings. Applications The couplings are usually installed in the top tube and down tube of a single-rider diamond frame. This enables the bicycle to be boxed small enough to avoid the extra fee most airlines charge to check a bicycle as luggage. They can also be installed in tandem and recumbent frames. Santana manufactures a "triplet (or quad) that can be transformed into a tandem by simply removing the center section of the frame." Characteristics The couplings are available in stainless steel, cromoly steel, and titanium and in different sizes, from to match the frame tubing in which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crankset
The crankset (in the US) or chainset (in the UK), is the component of a bicycle drivetrain that converts the reciprocating motion of the rider's legs into rotational motion used to drive the chain or belt, which in turn drives the rear wheel. It consists of one or more sprockets, also called ''chainrings'' or ''chainwheels'' attached to the '' cranks'', ''arms'', or ''crankarms'' to which the pedals attach. It is connected to the rider by the pedals, to the bicycle frame by the bottom bracket, and to the rear sprocket, cassette or freewheel via the chain. Parts Cranks The two ''cranks'', one on each side and usually mounted 180° apart, connect the bottom bracket axle to the pedals. Lengths Bicycle cranks can vary in length to accommodate different sized riders and different types of cycling. Crank length is measured from the center of the pedal spindle to the center of the bottom bracket spindle or axle. The larger bicycle component manufacturers typically of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Campagnolo
Campagnolo is an Italian manufacturer of high-end bicycle components with headquarters in Vicenza, Italy. The components are organised as groupsets (gruppi), and are a near-complete collection of a bicycle's mechanical parts. Campagnolo's flagship components are the Super Record, Record, and Chorus groupsets with all three representing their recent shift to 12-speed drivetrains. Super Record and Record are the top groupsets, followed by Chorus, Potenza, Centaur and Veloce. Campagnolo also produces aluminum and carbon wheels, as well as other components (like carbon fiber seat posts, and bottle-cages). History Founded by Tullio Campagnolo, the company began in 1933 in a Vicenza workshop. The founder was a racing cyclist in Italy in the 1920s who conceived several ideas while racing, such as the quick release mechanism for bicycle wheels, derailleurs, and the rod gear for gear changing. Campagnolo has been awarded more than 135 patents for innovations in cycling technology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Turbine
A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the direction of flow: * a rotating gas compressor * a combustor * a compressor-driving turbine. Additional components have to be added to the gas generator to suit its application. Common to all is an air inlet but with different configurations to suit the requirements of marine use, land use or flight at speeds varying from stationary to supersonic. A propelling nozzle is added to produce thrust for flight. An extra turbine is added to drive a propeller ( turboprop) or ducted fan (turbofan) to reduce fuel consumption (by increasing propulsive efficiency) at subsonic flight speeds. An extra turbine is also required to drive a helicopter rotor or land-vehicle transmission ( turboshaft), marine propeller or electrical generator (power turbine). Grea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hirth Joint
A Hirth joint or Hirth coupling is a type of mechanical connection named after its developeAlbert Hirth It is used to connect two pieces of a shaft together and is characterized by tapered teeth that mesh together on the end faces of each half shaft. Construction Hirth joints consist of radial teeth formed by grooves milled or ground into the end face of a cylindrical shaft. The teeth mesh around a ring, as the torque capacity of teeth increases with their diameter. This ring is arranged to be at the maximal possible diameter for the space available. The centre of a shaft is not toothed, as this would add little torque capacity to the coupling and the increasingly narrow teeth would become impractical to cut. For instance, a shaft of 60 mm diameter can be toothed in a 12 mm wide ring only (inner diameter is 36 mm) without jeopardizing the load-bearing capacity of the shaft. Tapered, symmetrical serrations are used. Profile angles of 60 and 90 degrees are used. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fretting
Fretting refers to wear and sometimes corrosion damage of loaded surfaces in contact while they encounter small oscillatory movements tangential to the surface. Fretting is caused by adhesion of contact surface asperities, which are subsequently broken again by the small movement. This breaking causes wear debris to be formed. If the debris and/or surface subsequently undergo chemical reaction, i.e., mainly oxidation, the mechanism is termed fretting corrosion. Fretting degrades the surface, leading to increased surface roughness and micropits, which reduces the fatigue strength of the components. The amplitude of the relative sliding motion is often in the order of micrometers to millimeters, but can be as low as 3 nanometers. Typically fretting is encountered in shrink fits, bearing seats, bolted parts, splines, and dovetail connections. Materials Steel Fretting damage in steel can be identified by the presence of a pitted surface and fine 'red' iron oxide dust resembl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Backlash (engineering)
In mechanical engineering, backlash, sometimes called lash, play, or slop, is a clearance or lost motion in a mechanism caused by gaps between the parts. It can be defined as "the maximum distance or angle through which any part of a mechanical system may be moved in one direction without applying appreciable force or motion to the next part in mechanical sequence."p. 1-8 An example, in the context of gears and gear trains, is the amount of clearance between mated gear teeth. It can be seen when the direction of movement is reversed and the slack or lost motion is taken up before the reversal of motion is complete. It can be heard from the railway couplings when a train reverses direction. Another example is in a valve train with mechanical tappets, where a certain range of lash is necessary for the valves to work properly. Depending on the application, backlash may or may not be desirable. Some amount of backlash is unavoidable in nearly all reversing mechanical couplings ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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