Blade Style

Rescue Knife designs often feature a modified Sheep Foot or Wharncliffe style blade. Emergency procedures may involve cutting through a jammed seat belt in the aftermath of a car crash. Clothing may also have to be cut through in order to free a victim or to gain venous access. Cutting through fibrous materials in such close proximity to the casualty is much safer if the knife being used has a blunt or rounded tip.

The Emerson Knives US Navy Search and Rescue Knife (SARK) has a partially serrated blade with a Wharncliffe style blade, similar to the Eickhorn Pocket Rescue Tool PRT XII. The Spyderco Atlantic Salt and Rescue 93 mm knives are blunt-ended Sheep Foot style blades. A serrated edge increases the effective cutting edge length by up to 24%. The sharpened recesssed curve has more linear cutting surface than a straight edge. Edge retention is also greater because cutting is started by the serrations' tips, easing the workload on the recessed edges, and protecting the sharp inside cutting curves which wear less over time.

A Secondary blade or seat belt cutter is a safety feature for use when cutting in close proximity to a living person. This may involve cutting through a jammed seat belt restraint or cutting through clothing. Incorporated into a slot in the handle it is used by positioning the fixed material within the slot and pulling the knife in the opposite direction.

Rescue Hook

The 'Rescue Hook' is a design variation where the blade tip has a blunt outer surface, and a sharpened inner crescent shaped edge. Many manufacturers have their own variants of this design. An example is the Eickhorn Pocket rescue Tool PRT XI.

Window Puncher / Glass Breaker

One-Handed Opening

The Emerson wave Hook, invented by Emerson Knives provides a solution to the one-handed opening of a folding knife. This opens the blade when the knife is withdrawn from a pocket.

Grasping the end of the handle between forefinger and thumb, the knife is drawn out and backwards. The hook protruding from the blade back catches on the pocket and opens the blade. If the knife is drawn out and backwards in one complete motion, the blade opens fully to the locked open position.

Another option is the thumb stud, which can be right or left handed or ambidextrous. This may be permanently riveted to the blade as most ambidextrous thumb studs are, or removable to allow for right or left handed positioning. The so-called ambidextrous thumb lug is attached to the back edge of the blade instead of the flat surface of the blade. The disadvantage of having a thumb stud or lug attached to the blade is that it may interfere with the cutting activity when using the knife. If the thumb stud is positioned too far along the blade it will compromise the blades usefulness, whilst if positioned too close to the handle, it will be difficult in practical use.

The blade opening, thumb hole-pull also allows one-handed opening. The cut-out portions of the blade are different shapes depending on the manufacturer. There are many variations such as the Spyderco Round Hole, the Tool Logic oval hole, the Byrd Knives, tear-drop shaped hole and the Leatherman oblong shaped thumb hole pull. The size of the thumb opening hole in Spyderco knives is increased to 14 mm diameter in military and rescue models, an allowance for gloved hand-use.

Thumb hole sizes in Spyderco knives varies from 11 mm in the Lava and Kopa knives, 12 mm in the Police knife, 13 mm in the UK Penknife and 14 mm. In the Assist and Atlantic Salt knives. The Spyderco Assist Knife has an added 'Cobra Hood', which is a raised border along the top edge of the spine cusp above the thumb hole. The 'Cobra Hood' makes blade opening easier when the thumb is not fully engaged in the thumb hole, for instance when the user is wearing gloves.

To open the blade with one hand, holding the knife in the palm of the hand at the base of the fingers, grasp the handle with the tips of the fingers, place the pad of the thumb in the thumb hole, then slide the blade away from the handle using the thumb. To close the blade with one hand, depress the lock release bar with the thumb, ensure the index finger is in a forward position at the front of the handle near the blade pivot. A gentle flick of the wrist causes the blade to fall forwards so that the unsharpened portion rests on the index finger. The blade can then be closed fully using the thumb.

Eickhorn Pocket Rescue Tools        Spyderco Rescue Knives