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Pantographic Knife
A pantographic knife or paratrooper knife is a folding knife whose blade is opened by a unique scissors method. The blade has a slightly longer tang than a folding knife heel. The handle is symmetrically segmented and articulated to fold away on both sides to grip the longer tang. The manner is similar to a butterfly knife (also called a Balisong knife after its modern place of origin)—with which it is often confused. Unlike the balisong knife handles that swing freely and independently, the pantographic knife uses a pantograph linkage to keep the handles aligned during opening and closing. The pantographic knife is very strong when compared to most other folding knife designs, being joined at several points and along several planes—this increases the force required to break the blade away from the handle. By enclosing the blade on both sides, double edged blades can be used. This knife is also known as a ''paratrooper knife'', although it was never issued as such. The mechani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pocketknife
A pocketknife is a knife with one or more blades that fold into the handle. They are also known as jackknives (jack-knife), folding knives, or may be referred to as a penknife, though a penknife may also be a specific kind of pocketknife. A typical blade length is . Pocketknives are versatile tools, and may be used for anything from whittling and woodcarving, to butchering small game, gutting and filleting small fish, aiding in the preparation of tinder and kindling for fires, boring holes in soft material, to opening an envelope, cutting twine, slicing a piece of fruit or as a means of self-defense. Specialised designs are also used for mushroom hunting and gardening. Pocketknives designed for gardening include pruning knives, which are folding knives with long curved blades used for pruning, trimming cuttings, taking buds and preparing material for grafting. History The earliest known pocketknives date to at least the early Iron Age. A pocketknife with a bone handle w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Butterfly Knife
A butterfly knife, also known as a Balisong, fan knife or Batangas knife, is a type of folding pocketknife that originated in the Philippines. Its distinct features are two handles counter-rotating around the tang such that, when closed, the blade is concealed within grooves in the handles. A latch holds the handles together, typically mounted on the one facing the cutting edge (the "bite handle"). The balisong was commonly used by Filipinos, especially those in the Tagalog region, as a self-defense and pocket utility knife. Hollow-grind balisongs were also used as straight razors before conventional razors were available in the Philippines. In the hands of a trained user, the knife blade can be brought to bear quickly using one hand. Manipulations, called "flipping", are performed for art or amusement. Blunt "trainer" versions of these knives are available and can be used to practice tricks without the risk of injury. The knife is now illegal or restricted in some countries ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pantograph
A pantograph (, from their original use for copying writing) is a mechanical linkage connected in a manner based on parallelograms so that the movement of one pen, in tracing an image, produces identical movements in a second pen. If a line drawing is traced by the first point, an identical, enlarged, or miniaturized copy will be drawn by a pen fixed to the other. Using the same principle, different kinds of pantographs are used for other forms of duplication in areas such as sculpting, minting, engraving, and milling. Because of the shape of the original device, a pantograph also refers to a kind of structure that can compress or extend like an accordion, forming a characteristic rhomboidal pattern. This can be found in extension arms for wall-mounted mirrors, temporary fences, pantographic knives, scissor lifts, and other scissor mechanisms such as the pantograph used on electric locomotives and trams. History The ancient Greek engineer Hero of Alexandria described ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linkage (mechanical)
A mechanical linkage is an assembly of systems connected to manage forces and movement. The movement of a body, or link, is studied using geometry so the link is considered to be rigid. The connections between links are modeled as providing ideal movement, pure rotation or sliding for example, and are called joints. A linkage modeled as a network of rigid links and ideal joints is called a kinematic chain. Linkages may be constructed from open chains, closed chains, or a combination of open and closed chains. Each link in a chain is connected by a joint to one or more other links. Thus, a kinematic chain can be modeled as a graph in which the links are paths and the joints are vertices, which is called a linkage graph. The movement of an ideal joint is generally associated with a subgroup of the group of Euclidean displacements. The number of parameters in the subgroup is called the degrees of freedom (DOF) of the joint. Mechanical linkages are usually designed to trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plane (mathematics)
In mathematics, a plane is a Euclidean ( flat), two-dimensional surface that extends indefinitely. A plane is the two-dimensional analogue of a point (zero dimensions), a line (one dimension) and three-dimensional space. Planes can arise as subspaces of some higher-dimensional space, as with one of a room's walls, infinitely extended, or they may enjoy an independent existence in their own right, as in the setting of two-dimensional Euclidean geometry. Sometimes the word ''plane'' is used more generally to describe a two-dimensional surface, for example the hyperbolic plane and elliptic plane. When working exclusively in two-dimensional Euclidean space, the definite article is used, so ''the'' plane refers to the whole space. Many fundamental tasks in mathematics, geometry, trigonometry, graph theory, and graphing are performed in a two-dimensional space, often in the plane. Euclidean geometry Euclid set forth the first great landmark of mathematical thought, an ax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Force
A force is an influence that can cause an Physical object, object to change its velocity unless counterbalanced by other forces. The concept of force makes the everyday notion of pushing or pulling mathematically precise. Because the Magnitude (mathematics), magnitude and Direction (geometry, geography), direction of a force are both important, force is a Euclidean vector, vector quantity. The SI unit of force is the newton (unit), newton (N), and force is often represented by the symbol . Force plays an important role in classical mechanics. The concept of force is central to all three of Newton's laws of motion. Types of forces often encountered in classical mechanics include Elasticity (physics), elastic, frictional, Normal force, contact or "normal" forces, and gravity, gravitational. The rotational version of force is torque, which produces angular acceleration, changes in the rotational speed of an object. In an extended body, each part often applies forces on the adjacent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blade
A blade is the portion of a tool, weapon, or machine with an edge that is designed to puncture, chop, slice or scrape surfaces or materials. Blades are typically made from materials that are harder than those they are to be used on. Historically, humans have made blades from flaking stones such as flint or obsidian, and from various metal such as copper, bronze and iron. Modern blades are often made of steel or ceramic. Blades are one of humanity's oldest tools, and continue to be used for combat, food preparation, and other purposes. Blades work by concentrating force on the cutting edge. Certain blades, such as those used on bread knives or saws, are serrated, further concentrating force on the point of each tooth. Uses During food preparation, knives are mainly used for slicing, chopping, and piercing. In combat, a blade may be used to slash or puncture, and may also be thrown or otherwise propelled. The function is to sever a nerve, muscle or tendon fibers, or blood ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paratrooper
A paratrooper is a military parachutist—someone trained to parachute into a military operation, and usually functioning as part of an airborne force. Military parachutists (troops) and parachutes were first used on a large scale during World War II for troop distribution and transportation. Paratroopers are often used in surprise attacks, to seize strategic objectives such as airfields or bridges. Overview Paratroopers jump out of airplanes and use parachutes to land safely on the ground. This is one of the three types of "forced entry" strategic techniques for entering a theater of war; the other two being by land and by water. Their tactical advantage of entering the battlefield from the air is that they can attack areas not directly accessible by other transport. The ability of air assault to enter the battlefield from any location allows paratroopers to evade emplaced fortifications that guard from attack from a specific direction. The possible use of paratroo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravity Knife
A gravity knife is a knife with a blade contained in its handle, and that opens its blade by the force of gravity. This mechanism of opening is fundamentally different from the switchblade, which extends its spring-propelled blade automatically upon the push of a button, switch, or fulcrum lever. The main purpose of gravity opening is that it allows opening and closing to be done ''one handed'', in situations where the other hand is occupied. Hence, historically they have been issued to parachutists to cut off caught lines, such as lines tangled in trees, a major potential use of the gravity knife. The gravity knife uses a button, trigger, or fulcrum lever to release the blade from both the open and the closed positions, and may use a side-folding or telescoping (out-the-front, or OTF) blade. While most military gravity knives utilize a locking blade design, other types may not mechanically lock open but rely instead upon friction to wedge the rear section of the blade against the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pantographic Knife
A pantographic knife or paratrooper knife is a folding knife whose blade is opened by a unique scissors method. The blade has a slightly longer tang than a folding knife heel. The handle is symmetrically segmented and articulated to fold away on both sides to grip the longer tang. The manner is similar to a butterfly knife (also called a Balisong knife after its modern place of origin)—with which it is often confused. Unlike the balisong knife handles that swing freely and independently, the pantographic knife uses a pantograph linkage to keep the handles aligned during opening and closing. The pantographic knife is very strong when compared to most other folding knife designs, being joined at several points and along several planes—this increases the force required to break the blade away from the handle. By enclosing the blade on both sides, double edged blades can be used. This knife is also known as a ''paratrooper knife'', although it was never issued as such. The mechani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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