A pantographic knife or paratrooper knife is a
folding knife
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 ty ...
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
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 bl ...
(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
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 dr ...
linkage
Linkage may refer to:
* ''Linkage'' (album), by J-pop singer Mami Kawada, released in 2010
*Linkage (graph theory), the maximum min-degree of any of its subgraphs
*Linkage (horse), an American Thoroughbred racehorse
* Linkage (hierarchical cluster ...
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
In physics, a force is an influence that can change the motion of an object. A force can cause an object with mass to change its velocity (e.g. moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a p ...
required to break the blade away from the handle. By enclosing the
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. Historic ...
on both sides, double edged blades can be used.
This knife is also known as a ''
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 ...
knife'', although it was never issued as such. The mechanism includes a collar that travels up the blade. This looks similar to an OTF
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 up ...
used by German paratroopers.
History
Examples of pantographic knives with patent markings D.R.G.M. (Deutsches Reich Gebrauchsmuster) indicate production in Germany during the war, but do not imply military issue. Although this design predates World War II, records of German paratroopers having genuinely been issued pantographic knives have not surfaced. To complicate identification, samples made with German army markings (brass handles with text in English language) seem to be post-war (1948) marketing attempts capitalizing on the term ''paratrooper''.
Function
In this illustration:
* Figure A shows the closed knife, with blade retracted.
* Figure B shows the pantographic legs opening. The collar is shown sliding down the blade.
* Figure C shows the blade almost extended.
* And finally, Figure D shows the pantographic legs folded together, making a handle that is half as long as when the knife was closed.
References
{{Knives
Pocket knives