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Backlash (gear)
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] |
Mechanical Engineering
Mechanical engineering is the study of physical machines that may involve force and movement. It is an engineering branch that combines engineering physics and mathematics principles with materials science, to design, analyze, manufacture, and maintain mechanical systems. It is one of the oldest and broadest of the engineering branches. Mechanical engineering requires an understanding of core areas including mechanics, dynamics, thermodynamics, materials science, structural analysis, and electricity. In addition to these core principles, mechanical engineers use tools such as computer-aided design (CAD), computer-aided manufacturing (CAM), and product lifecycle management to design and analyze manufacturing plants, industrial equipment and machinery, heating and cooling systems, transport systems, aircraft, watercraft, robotics, medical devices, weapons, and others. Mechanical engineering emerged as a field during the Industrial Revolution in Europe in the 18th ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diametral Pitch
A gear is a rotating circular machine part having cut teeth or, in the case of a cogwheel or gearwheel, inserted teeth (called ''cogs''), which mesh with another (compatible) toothed part to transmit (convert) torque and speed. The basic principle behind the operation of gears is analogous to the basic principle of levers. A gear may also be known informally as a cog. Geared devices can change the speed, torque, and direction of a power source. Gears of different sizes produce a change in torque, creating a mechanical advantage, through their ''gear ratio'', and thus may be considered a simple machine. The rotational speeds, and the torques, of two meshing gears differ in proportion to their diameters. The teeth on the two meshing gears all have the same shape. Two or more meshing gears, working in a sequence, are called a gear train or a ''transmission''. The gears in a transmission are analogous to the wheels in a crossed, belt pulley system. An advantage of gears is tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ball Screw
A ball screw (or ballscrew) is a mechanical linear actuator that translates rotational motion to linear motion with little friction. A threaded shaft provides a helical raceway for ball bearings which act as a precision screw. As well as being able to apply or withstand high thrust loads, they can do so with minimum internal friction. They are made to close tolerances and are therefore suitable for use in situations in which high precision is necessary. The ball assembly acts as the nut while the threaded shaft is the screw. In contrast to conventional leadscrews, ballscrews tend to be rather bulky, due to the need to have a mechanism to recirculate the balls. Another form of linear actuator based on a rotating rod is the threadless ballscrew, a.k.a. "rolling ring drive". In this design, three (or more) rolling-ring bearings are arranged symmetrically in a housing surrounding a smooth (threadless) actuator rod or shaft. The bearings are set at an angle to the rod, and this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jerzy
Jerzy is the Polish language, Polish version of the masculine given name George (given name), George. The most common nickname for Jerzy is Jurek (given name), Jurek (), which may also be used as an official first name. Occasionally the nickname Jerzyk may be used, which means "Common swift, swift" in Polish. People *Jerzy, ''nom de guerre'' of Ryszard Białous, Polish World War II resistance fighter * Jerzy Andrzejewski, Polish writer * Jerzy Bartmiński, Polish linguist and ethnologist * Jerzy Braun (other), several people * Jerzy Brzęczek, Polish footballer and manager * Jerzy Buzek, Polish politician and former Prime Minister * Jerzy Dudek, Polish footballer * Jerzy Fedorowicz, Polish actor and theatre director * Jerzy Ficowski, Polish poet and translator * Jerzy Grotowski, Polish theatre director and theorist * Jerzy Hoffman, Polish film director, screenwriter, and producer * Jerzy Jarniewicz, Polish poet, literary critic, translator and essayist * Jerzy Janowicz, Po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thou (length)
A thousandth of an inch is a derived unit of length in a system of units using inches. Equal to of an inch, a thousandth is commonly called a thou (used for both singular and plural) or particularly in North America a mil (plural mils). The words are shortened forms of the English and Latin words for "thousand" ( in Latin). In international engineering contexts, confusion can arise because ''mil'' is a formal unit name in North America but ''mil'' or ''mill'' is also a common colloquial clipped form of millimetre. The units are considerably different: a millimetre is approximately 39 mils. Contexts of use The thou, or mil, is most commonly used in engineering and manufacturing in non-metric countries. For example, in specifying: * The thickness of items such as paper, film, foil, wires, paint coatings, latex gloves, plastic sheeting, and fibers ** For example, most plastic ID cards are about in thickness. ** Card stock thickness in the United States, where mils are also c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Split Nut
A split nut is a nut that is split lengthwise into two pieces (opposed halves) so that its female thread may be opened and closed over the male thread of a bolt or leadscrew. This allows the nut, when open, to move along the screw without the screw turning (or, vice versa, to allow the screw to pass through the nut without turning). Then, when the nut is closed, it resumes the normal movement of a nut on a screw (in which axial travel is linked to rotational travel) A split nut assembly is often used in positioning systems, for example in the leadscrew of a lathe. It is one of the machine elements that makes single-point threading practical on manual (non- CNC) lathes. The very earliest screw-cutting lathes (in the late 18th and early 19th centuries) did not have them, but within a few decades, split nuts were common on lathes. The two halves of the nut have chamfered ends (60° to axis), which helps the threads to find engagement during the closing action. Usually the screw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Numerical Control
Numerical control (also computer numerical control, and commonly called CNC) is the automated control of machining tools (such as drills, lathes, mills, grinders, routers and 3D printers) by means of a computer. A CNC machine processes a piece of material (metal, plastic, wood, ceramic, or composite) to meet specifications by following coded programmed instructions and without a manual operator directly controlling the machining operation. A CNC machine is a motorized maneuverable tool and often a motorized maneuverable platform, which are both controlled by a computer, according to specific input instructions. Instructions are delivered to a CNC machine in the form of a sequential program of machine control instructions such as G-code and M-code, and then executed. The program can be written by a person or, far more often, generated by graphical computer-aided design (CAD) or computer-aided manufacturing (CAM) software. In the case of 3D printers, the part to be print ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trapezoidal Thread Forms
Trapezoidal thread forms are screw thread profiles with trapezoidal outlines. They are the most common forms used for leadscrews (power screws). They offer high strength and ease of manufacture. They are typically found where large loads are required, as in a vise or the leadscrew of a lathe. Standardized variations include multiple-start threads, left-hand threads, and self-centering threads (which are less likely to bind under lateral forces). The original trapezoidal thread form, and still probably the one most commonly encountered worldwide, with a 29° thread angle, is the Acme thread form ( ). The Acme thread was developed in 1894 as a profile well suited to power screws that has various advantages over the square thread,See: * Simpson, John and Proffitt, Michael, ed.s, "acme", ''Oxford English Dictionary: Additions Series'', vol. 3 (Oxford, England: Oxford University Press, 1997)p. 10.* The Acme thread was proposed by Albert Man Powell, then president of the Powell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bearing Surface
A bearing surface in mechanical engineering is the area of contact between two objects. It usually is used in reference to bolted joints and bearings, but can be applied to a wide variety of engineering applications. On a screw the bearing area loosely refers to the underside of the head. Strictly speaking, the bearing area refers to the area of the screw head that directly bears on the part being fastened. For a cylindrical bearing it is the projected area perpendicular to the applied force. On a spring the bearing area refers to the amount of area on the top or bottom surface of the spring in contact with the constraining part.. The ways of machine tools, such as dovetail slides, box ways, prismatic ways, and other types of machine slides are also bearing surfaces. See also *Babbitt, an alloy that covers a bearing surface *Bridge bearing * Pillow block bearing * Plain bearing A plain bearing, or more commonly sliding contact bearing and slide bearing (in railroading ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Machine Tool
A machine tool is a machine for handling or machining metal or other rigid materials, usually by cutting, boring, grinding, shearing, or other forms of deformations. Machine tools employ some sort of tool that does the cutting or shaping. All machine tools have some means of constraining the work piece and provide a guided movement of the parts of the machine. Thus, the relative movement between the workpiece and the cutting tool (which is called the toolpath) is controlled or constrained by the machine to at least some extent, rather than being entirely "offhand" or " freehand". It is a power-driven metal cutting machine which assists in managing the needed relative motion between cutting tool and the job that changes the size and shape of the job material. The precise definition of the term ''machine tool'' varies among users, as discussed below. While all machine tools are "machines that help people to make things", not all factory machines are machine tools. Today machi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screw Thread
A screw thread, often shortened to thread, is a helical structure used to convert between rotational and linear movement or force. A screw thread is a ridge wrapped around a cylinder or cone in the form of a helix, with the former being called a ''straight'' thread and the latter called a ''tapered'' thread. A screw thread is the essential feature of the screw as a simple machine and also as a threaded fastener. The mechanical advantage of a screw thread depends on its ''lead'', which is the linear distance the screw travels in one revolution. In most applications, the lead of a screw thread is chosen so that friction is sufficient to prevent linear motion being converted to rotary, that is so the screw does not slip even when linear force is applied, as long as no external rotational force is present. This characteristic is essential to the vast majority of its uses. The tightening of a fastener's screw thread is comparable to driving a wedge into a gap until it sticks fast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leadscrew
A leadscrew (or lead screw), also known as a power screw or translation screw,Bhandari, p. 202. is a screw used as a linkage in a machine, to translate turning motion into linear motion. Because of the large area of sliding contact between their male and female members, screw threads have larger frictional energy losses compared to other linkages. They are not typically used to carry high power, but more for intermittent use in low power actuator and positioner mechanisms. Leadscrews are commonly used in linear actuators, machine slides (such as in machine tools), vises, presses, and jacks.Shigley, p. 400. Leadscrews are a common component in electric linear actuators. Leadscrews are manufactured in the same way as other thread forms (they may be rolled, cut, or ground). A lead screw is sometimes used with a split nut (also called half nut) which allows the nut to be disengaged from the threads and moved axially, independently of the screw's rotation, when needed (s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
