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Lead (engineering)
Lead is the axial advance of a helix or screw during one complete turn (360°) The lead for a screw thread is the axial travel for a single revolution. ''Pitch'' is defined as the axial distance between adjacent threads on a helix or screw. In most screws, called "''single start''" screws, which have a single helical thread along their length, the lead and pitch are equal. They only differ in "''multiple start''" screws, which have several intertwined threads. In these screws, the lead is equal to the pitch multiplied by the number of "''starts''". Lead angle is the angle between the helix and a plane of rotation. It is the complement of the helix angle, and is used for convenience in worms and hobs. It is understood to be at the standard pitch diameter unless otherwise specified. The lead angle can be expressed as: :\mbox = \arctan \left( \frac \right) where :''l'' is lead of the helix :''dm'' is mean diameter of the helix In American literature ''λ'' is used to n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leads
Lead is a chemical element with symbol Pb and atomic number 82. Lead or The Lead may also refer to: Animal handling * Leash, or lead * Lead (leg), the leg that advances most in a quadruped's cantering or galloping stride * Lead (tack), a line used to lead a horse Arts, entertainment, and media Journalism * Lead (news), the leading news story or leading part of a news story * Lead, information from a source that leads to the uncovering of more interesting information * Lead paragraph, the opening paragraph of an article Music ;Concepts * Lead sheet, a musical score describing the essential elements of a song * Lead, type of voice, or patch, in synthesizer * Lead instrument * Lead vocalist * Guitar solo, a solo performed by the lead guitar ;Other * Lead (band), a Japanese hip-hop group * "Lead", a song by Matt Brouwer from ''Imagerical'' * ''The Lead'' (EP), an extended play by British girl group FLO Performance * Leading actor * Lead and follow, the direction or guida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Angle
Lead is the axial advance of a helix or screw during one complete turn (360°) The lead for a screw thread is the axial travel for a single revolution. ''Pitch'' is defined as the axial distance between adjacent threads on a helix or screw. In most screws, called "''single start''" screws, which have a single helical thread along their length, the lead and pitch are equal. They only differ in "''multiple start''" screws, which have several intertwined threads. In these screws, the lead is equal to the pitch multiplied by the number of "''starts''". Lead angle is the angle between the helix and a plane of rotation. It is the complement of the helix angle, and is used for convenience in worms and hobs. It is understood to be at the standard pitch diameter unless otherwise specified. The lead angle can be expressed as: :\mbox = \arctan \left( \frac \right) where :''l'' is lead of the helix :''dm'' is mean diameter of the helix In American literature ''λ'' is used to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helix
A helix () is a shape like a corkscrew or spiral staircase. It is a type of smooth space curve with tangent lines at a constant angle to a fixed axis. Helices are important in biology, as the DNA molecule is formed as two intertwined helices, and many proteins have helical substructures, known as alpha helices. The word ''helix'' comes from the Greek word ''ἕλιξ'', "twisted, curved". A "filled-in" helix – for example, a "spiral" (helical) ramp – is a surface called ''helicoid''. Properties and types The ''pitch'' of a helix is the height of one complete helix turn, measured parallel to the axis of the helix. A double helix consists of two (typically congruent) helices with the same axis, differing by a translation along the axis. A circular helix (i.e. one with constant radius) has constant band curvature and constant torsion. A ''conic helix'', also known as a ''conic spiral'', may be defined as a spiral on a conic surface, with the distance to the apex an expo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screw (simple Machine)
A screw is a mechanism that converts rotational motion to linear motion, and a torque (rotational force) to a linear force. It is one of the six classical simple machines. The most common form consists of a cylindrical shaft with helical grooves or ridges called '' threads'' around the outside. The screw passes through a hole in another object or medium, with threads on the inside of the hole that mesh with the screw's threads. When the shaft of the screw is rotated relative to the stationary threads, the screw moves along its axis relative to the medium surrounding it; for example rotating a wood screw forces it into wood. In screw mechanisms, either the screw shaft can rotate through a threaded hole in a stationary object, or a threaded collar such as a nut can rotate around a stationary screw shaft. Geometrically, a screw can be viewed as a narrow inclined plane wrapped around a cylinder. Like the other simple machines a screw can amplify force; a small rotational force (tor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Gear Manufacturers Association
The American Gear Manufacturers Association or AGMA is the trade group of companies involved in gears, couplings and related power transmission components and equipment. AGMA was founded in 1916; as of December 30, 2016, there were 456 member companies listed on the association's website. AGMA is accredited by the American National Standards Institute (ANSI) to write all U.S. standards on gearing, including terminology, nominal dimensions, tolerances, and tools for manufacturing and control. In 1993, AGMA became the Secretariat for Technical Committee 60 (TC 60) of ISO. TC 60 is the committee responsible for developing all international gearing standards. In addition to the position of Secretariat, AGMA also chairs one-third of the active ISO Working Groups related to gearing. AGMA hosts the industry's trade showGear Expo every two years. Gear Expo is the only trade show dedicated to the complete gear manufacturing process. The AGMA Fall Technical Meeting provides paper prese ... [...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 thro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plane Of Rotation
In geometry, a plane of rotation is an abstract object used to describe or visualize rotations in space. In three dimensions it is an alternative to the axis of rotation, but unlike the axis of rotation it can be used in other dimensions, such as two, four or more dimensions. Mathematically such planes can be described in a number of ways. They can be described in terms of planes and angles of rotation. They can be associated with bivectors from geometric algebra. They are related to the eigenvalues and eigenvectors of a rotation matrix. And in particular dimensions they are related to other algebraic and geometric properties, which can then be generalised to other dimensions. Planes of rotation are not used much in two and three dimensions, as in two dimensions there is only one plane so identifying the plane of rotation is trivial and rarely done, while in three dimensions the axis of rotation serves the same purpose and is the more established approach. The main use for them is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helix Angle
In mechanical engineering, a helix angle is the angle between any helix and an axial line on its right, circular cylinder or cone. Common applications are screws, helical gears, and worm gears. The helix angle references the axis of the cylinder, distinguishing it from the lead angle, which references a line perpendicular to the axis. Naturally, the helix angle is the geometric complement of the lead angle. The helix angle is measured in degrees. Concept In terms specific to screws, the helix angle can be found by unraveling the helix from the screw, representing the section as a right triangle, and calculating the angle that is formed. Note that while the terminology directly refers to screws, these concepts are analogous to most mechanical applications of the helix angle. The helix angle can be expressed as: ''\mbox = \arctan \left( \frac \right)'' where :''l'' is lead of the screw or gear :''rm'' is mean radius of the screw thread or gear Applications The helix angle is c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Pitch Diameter
This page lists the standard US nomenclature used in the description of mechanical gear construction and function, together with definitions of the terms. The terminology was established by the American Gear Manufacturers Association (AGMA), under accreditation from the American National Standards Institute (ANSI). Addendum The addendum is the height by which a tooth of a gear projects beyond (outside for external, or inside for internal) the standard pitch circle or pitch line; also, the radial distance between the pitch diameter and the outside diameter. Addendum angle Addendum angle in a bevel gear, is the angle between face cone and pitch cone. Addendum circle The addendum circle coincides with the tops of the teeth of a gear and is concentric with the standard (reference) pitch circle and radially distant from it by the amount of the addendum. For external gears, the addendum circle lies on the outside cylinder while on internal gears the addendum circle lies on th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Gear Nomenclature
This page lists the standard US nomenclature used in the description of mechanical gear construction and function, together with definitions of the terms. The terminology was established by the American Gear Manufacturers Association (AGMA), under accreditation from the American National Standards Institute (ANSI). Addendum The addendum is the height by which a tooth of a gear projects beyond (outside for external, or inside for internal) the standard pitch circle or pitch line; also, the radial distance between the pitch diameter and the outside diameter. Addendum angle Addendum angle in a bevel gear, is the angle between face cone and pitch cone. Addendum circle The addendum circle coincides with the tops of the teeth of a gear and is concentric with the standard (reference) pitch circle and radially distant from it by the amount of the addendum. For external gears, the addendum circle lies on the outside cylinder while on internal gears the addendum circle lies on th ... [...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 (simple machine), screw used as a linkage (mechanical), linkage in a machine, to translate Rotation, turning motion into linear motion. Because of the large area of sliding contact between their gender of connectors and fasteners, 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), vise (tool), vises, mechanical press, presses, and jack (device), 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 threading (manufacturing), rolled, cut, or ground). A lead screw is sometimes used with a spli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gears
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 t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
