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Detent
A detent is a mechanical or magnetic means to resist or arrest the movement of a mechanical device. Such a device can be anything ranging from a simple metal pin to a machine. The term is also used for the method involved. Magnetic detents are most often used to divide a shaft rotation into discrete increments. Magnetic detents are inherent in some types of electric motors, most often stepper motors. Mechanics Arresting movement Ratchet and pawl The ratchet-and- pawl design arrests movements by employing a small gravity- or spring-actuated lever paired with a notched wheel. The lever is mounted on a pivot point in proximity to the wheel. The vertical angle of the sides of the notches that face the direction of rotation desired is generally very acute (45 degrees or less), so that as the wheel rotates in that direction, the end of the lever is easily lifted or pushed out and over the top of a notch. Following this, the lever drops into the next notch and the next et cetera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ball Detent
A ball detent is a simple mechanical arrangement used to hold a moving part in a temporarily fixed position relative to another part. Usually the moving parts slide with respect to each other, or one part rotates within the other. The ball is a single, usually metal sphere, sliding within a bored cylinder, against the pressure of a spring, which pushes the ball against the other part of the mechanism, which carries the detent - which can be as simple as a hole of smaller diameter than the ball. When the hole is in line with the cylinder, the ball is partially pushed into the hole under spring pressure, holding the parts at that position. Additional force applied to the moving parts will compress the spring, causing the ball to be depressed back into its cylinder, and allowing the parts to move to another position. Applications Ball detents are commonly found in the selector mechanism of a gearbox, holding the selector rods in the correct position to engage the desired gear. Othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stepper Motor
A stepper motor, also known as step motor or stepping motor,Clarence W. de Silva. Mechatronics: An Integrated Approach (2005). CRC Press. p. 675. "The terms ''stepper motor'', ''stepping motor'', and ''step motor'' are synonymous and are often used interchangeably." is a brushless DC electric motor that rotates in a series of small and discrete angular steps. Stepper motors can be set to any given step position without needing a Rotary encoder, position sensor for feedback. The step position can be rapidly increased or decreased to create continuous rotation, or the motor can be ordered to actively hold its position at one given step. Motors vary in size, speed, step resolution, and torque. Switched reluctance motors are very large stepping motors with a reduced pole count. They generally employ closed-loop commutator (electric), commutators. Mechanism Brushed DC motors rotate continuously when DC voltage is applied to their terminals. The stepper motor is known for its proper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scroll Wheel
A scroll wheel is a wheel used for scrolling. The term usually refers to such wheels found on computer mouse, computer mice (where they can also be called a mouse wheel). It is often made of hard plastic with a rubbery surface, centred around an internal rotary encoder. It is usually located between the left and right mouse buttons and is positioned perpendicular to the mouse surface. Sometimes the wheel can be pressed left and right, which is actually just two additional macros buttons. Functionality The scroll wheel is placed horizontally between the mouse buttons and commonly uses vertical scrolling, wherein rolling the wheel from the bottom side to the top is known as scrolling "upward" or "forward", while the reverse, i.e. rolling the wheel from the top side to the bottom, is known as scrolling "downward" or "backward". In a graphical user interface, the "upward" motion moves contents of the window downward (and the scrollbar thumb, if present, upward), and vice versa. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotary Switch
A rotary switch is a switch operated by rotation. These are often chosen when more than 2 positions are needed, such as a three-speed fan or a CB radio with multiple frequencies of reception or "channels". A rotary switch consists of a spindle or "rotor" that has a contact arm or "spoke" which projects from its surface like a cam. It has an array of terminals, arranged in a circle around the rotor, each of which serves as a contact for the "spoke" through which any one of a number of different electrical circuit An electrical network is an interconnection of electrical components (e.g., battery (electricity), batteries, resistors, inductors, capacitors, switches, transistors) or a model of such an interconnection, consisting of electrical elements (e. ...s can be connected to the rotor. The switch is layered to allow the use of multiple poles; each layer is equivalent to one pole. Alternatively the rotation can be limited to a fraction (half; third etc.) of a circle a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Numerical Control
Computer numerical control (CNC) or CNC machining is the automated control of machine tools by a computer. It is an evolution of numerical control (NC), where machine tools are directly managed by data storage media such as punched cards or punched tape. Because CNC allows for easier programming, modification, and real-time adjustments, it has gradually replaced NC as computing costs declined. 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 printed is "sliced" before the instructions (or the prog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camera
A camera is an instrument used to capture and store images and videos, either digitally via an electronic image sensor, or chemically via a light-sensitive material such as photographic film. As a pivotal technology in the fields of photography and videography, cameras have played a significant role in the progression of visual arts, media, entertainment, surveillance, and scientific research. The invention of the camera dates back to the 19th century and has since evolved with advancements in technology, leading to a vast array of types and models in the 21st century. Cameras function through a combination of multiple mechanical components and principles. These include exposure control, which regulates the amount of light reaching the sensor or film; the lens, which focuses the light; the viewfinder, which allows the user to preview the scene; and the film or sensor, which captures the image. Several types of camera exist, each suited to specific uses and offering unique cap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shutter (photography)
In photography, a shutter is a device that allows light to pass for a determined period, exposing photographic film or a photosensitive digital sensor to light in order to capture a permanent image of a scene. A shutter can also be used to allow pulses of light to pass outwards, as seen in a movie projector or a signal lamp. A shutter of variable speed is used to control exposure time of the film. The shutter is constructed so that it automatically closes after a certain required time interval. The speed of the shutter is controlled either automatically by the camera based on the overall settings of the camera, manually through digital settings, or manually by a ring outside the camera on which various timings are marked. Camera shutter Camera shutters can be fitted in several positions: * Leaf shutters are usually fitted within a lens assembly (''central shutter''), or more rarely immediately behind (''behind-the-lens shutter'') or, even more rarely, in front of a lens, and s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Mouse
A computer mouse (plural mice; also mouses) is a hand-held pointing device that detects Plane (mathematics), two-dimensional motion relative to a surface. This motion is typically translated into the motion of the Cursor (user interface)#Pointer, pointer (called a cursor) on a computer monitor, display, which allows a smooth control of the graphical user interface of a computer. The first public demonstration of a mouse controlling a computer system was done by Doug Engelbart in 1968 as part of the Mother of All Demos. Mice originally used two separate wheels to directly track movement across a surface: one in the x-dimension and one in the Y. Later, the standard design shifted to use a ball rolling on a surface to detect motion, in turn connected to internal rollers. Most modern mice use optical mouse, optical movement detection with no moving parts. Though originally all mice were connected to a computer by a cable, many modern mice are cordless, relying on short-range rad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screw
A screw is an externally helical threaded fastener capable of being tightened or released by a twisting force (torque) to the screw head, head. The most common uses of screws are to hold objects together and there are many forms for a variety of materials. Screws might be inserted into holes in assembled parts or a screw may form its own thread. The #Differentiation between bolt and screw, difference between a screw and a bolt is that the latter is designed to be tightened or released by torquing a Nut (hardware), nut. The screw head on one end has a slot or other feature that commonly requires a tool to transfer the twisting force. Common tools for driving screws include screwdrivers, wrenches, coins and hex keys. The head is usually larger than the body, which provides a ''bearing surface'' and keeps the screw from being driven deeper than its length; an exception being the ''set screw'' (aka grub screw). The cylindrical portion of the screw from the underside of the head t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ratchet Wrench
A socket wrench (or socket spanner) is a type of spanner (or wrench in North American English) that uses a closed ''socket'' format, rather than a typical open wrench/spanner to turn a fastener, typically in the form of a nut or bolt. The most prevalent form is the ratcheting socket wrench, often informally called a ratchet. A ratchet incorporates a reversible ratcheting mechanism which allows the user to pivot the tool back and forth to turn its socket instead of removing and repositioning a wrench to do so. Other common methods of driving sockets include pneumatic impact wrenches, hydraulic torque wrenches, torque multipliers and breaker bars. Some lesser known hybrid drivers include striking wrench tools with square drive, and hydraulic impact wrenches (typically powered by on site hydraulic power such as present with military tanks, and many rail car applications). Interchangeable sockets The basic contemporary form of socket is hexagonal, referred to as "6-point" for t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wind-up Toy
A wind-up toy is an automaton toy powered by a clockwork motor. Background Automata built for the sake of art, amusement, and simulation have been described since antiquity, in cases such as Heron of Alexandria designing clockwork birds during the Hellenistic Period. Leonardo da Vinci is frequently credited with constructing a mechanical lion, which he presented to King Francois I in Lyon in 1515. Although no record of the device's original designs remain, a recreation of this piece is housed at the Château du Clos Lucé. Some misinformation exists with regards to Regiomontanus's contribution, and his supposed construction of a flight-capable mechanical eagle and fly, which are frequently credited as the first wind-up toys. This story of an eagle which flew from Nuremberg to greet Friedrich III, alongside that of a fly which could circulate the room before returning to its inventor's hand, was spread by Petrus Ramus after a visit to Nuremberg in 1571, and is apparently fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
