|
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 ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tool
A tool is an object that can extend an individual's ability to modify features of the surrounding environment or help them accomplish a particular task. Although many 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 stone, bone, and wood, were used for preparation of food, hunting, manufacture of weapons, and working of materials to produce clothing and useful artifacts. The development of metalworking made additional types of tools possible. Harnessing energy sources, such as animal power, wind, or steam, allowed increasingly complex tools to produce an even larger range of items, with the Industrial Revolution marking an inflection point in the use of tools. The introduction of widespread automation in the 19th and 20th centuries allowed tools to operate with minimal human supervision, further increasing the productivity of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Door Dogs
A door is a hinged or otherwise movable barrier that allows ingress (entry) into and egress (exit) from an enclosure. The created opening in the wall is a ''doorway'' or ''portal''. A door's essential and primary purpose is to provide security by controlling access to the doorway (portal). Conventionally, it is a panel that fits into the doorway of a building, room, or vehicle. Doors are generally made of a material suited to the door's task. They are commonly attached by hinges, but can move by other means, such as slides or counterbalancing. The door may be able to move in various ways (at angles away from the doorway/portal, by sliding on a plane parallel to the frame, by folding in angles on a parallel plane, or by spinning along an axis at the center of the frame) to allow or prevent ingress or egress. In most cases, a door's interior matches its exterior side. But in other cases (e.g., a vehicle door) the two sides are radically different. Many doors incorporate locking m ... [...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. A vise grip is not a vise but a pair of lever-actuated locking pliers. 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 nut that allows the screw to engage or disengage with a half-turn of the handle. When disengaged the movable jaw may be moved in or out throughout its entire range of motion, vastly speeding up the process of adjustment. Common thread types are Acme thread, Acme and buttress thread, buttress. Traditional workbench ... [...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 of the industrial-era type of 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 he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timber Framing
Timber framing (german: Holzfachwerk) and "post-and-beam" construction are traditional methods of building with heavy timbers, creating structures using squared-off and carefully fitted and joined timbers with joints secured by large wooden pegs. If the structural frame of 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 dimensional lumber. Hewing this with broadaxes, adzes, and draw knives and using hand-powered braces and augers (brace and bit) and other woodworking tools, artisans or framers could gradually assemble a building. Since this building method has been used for thousands of years in many parts of the world, many styles ... [...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 Brit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lathe Dog
A lathe dog is a mechanical device typically made of cast iron, steel or aluminum that transmits rotary motion from a faceplate to a workpiece mounted between centers in a lathe. The tail of the dog is rotated by a slot in a driving faceplate, a stud mounted on a faceplate, or sometimes a side of a chuck jaw. The workpiece passes through an aperture in the dog into which the work is secured by one or more setscrews or a clamp arrangement. The maximum cross sectional dimension of the workpiece is limited by the dimensions of the dog aperture. Lathe dogs are provided in ''straight tail'' or ''bent tail'' form, and may be ''single tail'' or ''double tail''. A lathe dog designed to hold square, rectangular or odd-shaped work and having a moveable portion secured typically by two cap screws is called a ''clamp dog''. Bent tail dogs are able to engage directly with a driving faceplate slot or a chuck jaw but can crowd work off centre if clearance is not present between the dog tail and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Automatic Transmission
An automatic transmission (sometimes abbreviated to auto or AT) is a multi-speed transmission used in internal combustion engine-based motor vehicles that does not require any input from the driver to change forward gears under normal driving conditions. It typically includes a transmission, axle, and differential in one integrated assembly, thus technically becoming a transaxle. The most common type of automatic transmission is the hydraulic automatic, which uses a planetary gearset, hydraulic controls, and a torque converter. Other types of automatic transmissions include continuously variable transmissions (CVT), automated manual transmissions (AMT), and dual-clutch transmissions (DCT). An electronic automatic transmission (EAT) may also be called an electronically controlled transmission (ECT), or electronic automatic transaxle (EATX). A hydraulic automatic transmission may also colloquially called a " slushbox" or simply a "torque converter", although the latter term c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmission (mechanics)
Propulsion transmission is the mode of transmitting and controlling propulsion power of a machine. The term ''transmission'' properly refers to the whole drivetrain, including clutch, gearbox, prop shaft (for rear-wheel drive vehicles), differential, and final drive shafts. In the United States the term is sometimes used in casual speech to refer more specifically to the gearbox alone, and detailed usage differs. The transmission reduces the higher engine speed to the slower wheel speed, increasing torque in the process. Transmissions are also used on pedal bicycles, fixed machines, and where different rotational speeds and torques are adapted. Often, a transmission has multiple gear ratios (or simply "gears") with the ability to switch between them as the speed varies. This switching may be done manually (by the operator) or automatically (by a control unit). Directional (forward and reverse) control may also be provided. Single-ratio transmissions also exist, which simply cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clutch Dog
A dog clutch (also known as a positive clutch or dog gears) is a type of clutch that couples two rotating shafts or other rotating components by engagement of interlocking teeth or dogs rather than by friction. The two parts of the clutch are designed such that one will push the other, causing both to rotate at the same speed and will never slip. In engineering, a "dog" is a tool or device used to lock two components in relation to each other. Dog clutches are used where slip is undesirable and/or the clutch is not used to control torque. Without slippage, dog clutches are not affected by wear in the same way that friction clutches are, but result in shock when shafts of different speeds are engaged. For this reason they are best used when sudden starting action is acceptable and the inertia of the system is small. Dog clutches are used inside constant-mesh manual transmissions to lock different gears to the rotating input and output shafts. A synchromesh arrangement ensures smoo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andiron
An andiron or firedog, fire-dog or fire dog is a bracket support, normally found in pairs, on which logs are laid for burning in an open fireplace, so that air may circulate under the firewood, allowing better burning and less smoke. They generally consist of a tall vertical element at the front, with at least two legs. This stops the logs from rolling out into the room, and may be highly decorative. The other element is one or more low horizontal pieces stretching back and serving to hold the logs off the bottom of the fireplace. An andiron is sometimes called a ''dog'' or ''dog-iron''. Before the Renaissance, European andirons were almost invariably made entirely of iron and were of comparatively plain design. Indeed, andirons and firebacks were one of the first types of object to be commonly made in cast iron, a trend which in England began in the 1540s: until the nineteenth century cast iron was too brittle for many uses, but andirons carried light loads and this was no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
