Gravity knife

[1] 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.

[2] Factory-made gravity knives have various types of buttons, triggers, and fulcrum levers, which usually are used to release the blade from both the open and the closed positions.

'paratrooper knife') was initially issued to German flight crews and paratroops, primarily for the purpose of cutting a trapped parachutist from his rigging in case he landed with a tangled parachute, or became entangled in trees or in the water with the shroud lines.

Though not intended for use as a fighting knife in the first place, the LGK was introduced to the 1st Skijäger Division and SS units on the Eastern Front to be used primarily as a close combat weapon from 1944 on.

The Type I LGK (three manufacturers, five WWII variations) has wood scales (handle), was made from 1937 to 1943, and unlike successive models has no takedown capability.

On the other side of the Iron Curtain, in the German Democratic Republic, WWII gravity knives were refurbished and re-issued to the paratroopers and pilots until the existing stock was gone.

[6] Under the initial wartime contract, George Ibberson & Co. made 500 gravity knives for issue to the SOE and other special forces.

These Sheffield gravity knives had smooth wood or textured plastic scales, but were otherwise identical in features and operation to the Type I Flieger-Kappmesser, with a locking gravity-deployed blade and a folding rigging spike or awl.

In addition to the knife blade, SOE close combat instructors found that the folding rigging spike was useful for silent killing of sentries by opening the carotid artery on the neck.

[3] Modern (post 1965) folding stilettos imported or distributed in the U.S. now have blade heels that are intentionally pointed and ratchet against the lockback mechanism, preventing inertia opening.

The addition of the toggle, which is attached to an internal bellcrank-arm, will lift the lockback mechanism to allow the blade to swing more easily.

[9] In some countries, such as the United Kingdom, Canada, and in some U.S. states, a gravity knife is proscribed under the law as a prohibited weapon, with attendant criminal penalties.