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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 mechanism includes a collar that travels up the blade. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pocketknife
A pocketknife (also spelled as pocket knife) is a knife with one or more blades that fold into the handle. They are also known as jackknives, folding knives, Everyday carry, EDC knife, 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 Wood carving, woodcarving, to butchering Game (hunting), 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 fruits and vegetables or as a means of self-defense. Pocketknives may also be used in conjunction with other tools and equipment for woodcraft and bushcraft. 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, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Butterfly Knife
A balisong, also known as a butterfly knife, 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 sometimes holds the handles together; typically mounted on the one facing the cutting edge (the "bite handle"). An exceptionally large balisong is called a balisword. The balisong was commonly used by Filipinos, especially those in the Tagalog region, as self-defense and a pocket utility knife. Hollow-grind balisongs were also used as straight razors before conventional razors were made available in the Philippines. In the hands of a trained user, the knife blade can be brought out to bear quickly using one hand. Manipulations, called "flipping", are performed for art or amusement. Blunt "trainer" versions of these knives are also available and can be used to practice tricks witho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pantograph
A pantograph (, from their original use for copying writing) is a Linkage (mechanical), 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, Mint (facility), minting, engraving, and Milling (machining), milling. History The ancient Greek engineer Hero of Alexandria described pantographs in his work ''Mechanics''. In 1603, Christoph Scheiner used a pantograph to copy and scale diagrams, and wrote about the invention over 27 years later, in ''"Pantographice seu Ars delineandi res quaslibet per parallelogrammum lineare seu cavum"'' (Rome 1631). One arm of the pantograph contained a small pointer, while the oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linkage (mechanical)
A mechanical linkage is an assembly of systems connected so as to manage forces and Motion, movement. The movement of a body, or link, is studied using geometry so the link is considered to be Rigid body, rigid. The connections between links are modeled as providing ideal movement, pure rotation or Sliding (motion), 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 geometry, Euclidean displacements. The number of parameters in the subgroup is called the degree of freedom (mecha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plane (mathematics)
In mathematics, a plane is a two-dimensional space or flat surface that extends indefinitely. A plane is the two-dimensional analogue of a point (zero dimensions), a line (one dimension) and three-dimensional space. When working exclusively in two-dimensional Euclidean space, the definite article is used, so ''the'' Euclidean plane refers to the whole space. Several notions of a plane may be defined. The Euclidean plane follows Euclidean geometry Euclidean geometry is a mathematical system attributed to ancient Greek mathematics, Greek mathematician Euclid, which he described in his textbook on geometry, ''Euclid's Elements, Elements''. Euclid's approach consists in assuming a small set ..., and in particular the parallel postulate. A projective plane may be constructed by adding "points at infinity" where two otherwise parallel lines would intersect, so that every pair of lines intersects in exactly one point. The elliptic plane may be further defined by adding a metr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Force
In physics, a force is an influence that can cause an Physical object, object to change its velocity unless counterbalanced by other forces. In mechanics, force makes ideas like '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 applies forces on the adjacent pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blade
A blade is the Sharpness (cutting), sharp, cutting portion of a tool, weapon, or machine, specifically designed to puncture, chop, slice, or scrape surfaces or materials. Blades are typically made from materials that are harder than those they are intended to cut. This includes early examples made from flaked stones like flint or obsidian, evolving through the ages into metal forms like copper, bronze, and iron, and culminating in modern versions made from steel or ceramics. Serving as one of humanity's oldest tools, blades continue to have wide-ranging applications, including in combat, cooking, and various other everyday and specialized tasks. Blades function by concentrating force at the cutting edge. Design variations, such as serrated edges found on bread knives and saws, serve to enhance this force concentration, adapting blades for specific functions and materials. Blades thus hold a significant place both historically and in contemporary society, reflecting an evolution i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paratrooper
A paratrooper or military parachutist is a soldier trained to conduct military operations by parachuting directly into an area of operations, usually as part of a large airborne forces unit. Traditionally paratroopers fight only as light infantry armed with small arms and light weapons, although some paratroopers can also function as artillerymen or mechanized infantry by utilizing field guns, infantry fighting vehicles and light tanks that are often used in surprise attacks to seize strategic positions behind enemy lines such as airfields, bridges and major roads. Overview Paratroopers jump out of aircraft 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 (warfare), 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 airbo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airborne Forces
Airborne forces are ground combat units carried by aircraft and airdropped into battle zones, typically by parachute drop. Parachute-qualified infantry and support personnel serving in airborne units are also known as paratroopers. The main advantage of airborne forces is their ability to be deployed into combat zones without a land passage, as long as the airspace is accessible. Formations of airborne forces are limited only by the number and size of their transport aircraft; a sizeable force can appear "out of the sky" behind enemy lines in merely hours if not minutes, an action known as ''vertical envelopment''. Airborne forces typically lack enough supplies for prolonged combat and so they are used for establishing an airhead to bring in larger forces before carrying out other combat objectives. Some infantry fighting vehicles have also been modified for paradropping with infantry to provide heavier firepower. Protocol I of the Geneva Conventions protects parachutis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravity Knife
A gravity knife is a knife with a blade contained in its handle, which opens its blade through 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 to allow opening and closing to be done with one hand, in situations where the other is occupied. Hence, historically, parachutists have been issued them 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 blade's rear section against the handle's interior ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fallschirmjäger
The () were the airborne forces branch of the Luftwaffe before and during World War II. They were the first paratroopers to be committed in large-scale airborne operations. They were commanded by Kurt Student, the Luftwaffe's second-in-command. Between the wars During the interwar years, the rapid development of aircraft and aviation technology drew the attention of imaginative military planners. The idea of aerially inserting a large body of troops inside enemy territory was proposed during World War I by Brigadier General Billy Mitchell (general), Billy Mitchell, commander of the United States Army Air Corps, U.S. Army Air Corps in France.Ailsby, Christopher: ''Hitler's Sky Warriors: German Paratroopers in Action, 1939–1945'', p. 12. Spellmount Limited, 2000. However, the Allies of World War I, Entente High Command was forced to abandon the idea, as it was unprepared for such an undertaking, both logistically and in materiel. Among the first to recognize the potential ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the world's countries participated, with many nations mobilising all resources in pursuit of total war. Tanks in World War II, Tanks and Air warfare of World War II, aircraft played major roles, enabling the strategic bombing of cities and delivery of the Atomic bombings of Hiroshima and Nagasaki, first and only nuclear weapons ever used in war. World War II is the List of wars by death toll, deadliest conflict in history, causing World War II casualties, the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Allied-occupied Germany, Germany, Allied-occupied Austria, Austria, Occupation of Japan, Japan, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
