Assisted Opening Knives

Assisted Opening Knives

shrade assisted opening knife image

An assisted-opening knife is a type of folding knife which uses an internal mechanism to finish the opening of the blade once the user has partially opened it using a flipper or thumb-stud attached to the blade. 

Assisted opening knives merge function and speed to create a mechanism that opens a blade as fast and smooth as a switchblade. The difference between automatic knives and spring assisted knives is how the blade is deployed. An automatic knife deploys the blade on its own (no exterior finger force) with a trigger/button. A spring assisted knife needs an external force to engage the spring. When the knife is in the closed position, the blade is held in place by means of torsion springs and an additional blade lock (optional). As the user applies manual pressure to the thumbstud to open the knife, a mechanism such as a torsion spring moves along a track in the liner and rapidly rotates the blade into the open and locked position.

Other trade names for assisted-opening knives are: Forward Action Spring Technology, A/O Knife, Torsion Assist Knife, Assisted Knife, Spring Assist Knife, Spring Assisted Knife, Quick Release, Quick Draw, Alternative Automatic, Outburst, SpeedSafe, Blade Launcher, S.A.T (SOG Assisted Technology), and the Semi-Auto.

Assisted Opening Knives

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1660 Kershaw Leek Knife silver plain Blade handle *New Blem* assisted opener

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SOG Reactor 8Cr13MoV Folding Blade Multi Tool Assisted Pliers Pocket Knife

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Kershaw Speedsafe Assisted Opening 8Cr13MoV Dagger Blade Folding Pocket Knife

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Kershaw Malt Modified Tanto 8Cr13MoV Blade Assisted Open Folding Pocket Knife

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KERSHAW 1336 HALOGEN SPEED SAFE ASSISTED OPENING KNIFE CARBON FIBER

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Kershaw Dividend Folding Knife 420HC Steel Blade Gray Anodized Aluminum Handle

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KERSHAW 1660 LEEK Stainless Speed-Safe assisted framelock knife / clip USA NEW!

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New Exclusive Kershaw Leek Folding Knife, BlackWash Blade w/ OD Handle 1660OLBW

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12" HUGE ASSISTED OPENING Folding Pocket Knife Stonewashed with Pocket Clip

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Gerber Highbrow Compact Urban Blue FE Assisted Opening Knife 7Cr Steel 2.8 Blade

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Kershaw 1600 Chive Stainless Steel Assisted Opening Pocket Knife

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Kershaw NATRIX Black Flipper SpeedSafe Assisted Opening 4.25" Knife BOX 7007BLK

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KERSHAW, KEN ONION LEEK 1660ST, ASSISTED OPENING, STAINLESS STEEL KNIFE

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Smith And Wesson M&P Assisted Open Emergency Rescue Folding Knife 1100078

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Kershaw 1955 Black Showtime Spring Assisted Open Folding Knife Pocket Folder

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KERSHAW 2335 AM-3 Black G10 Assisted Opening Framelock Knife 3 3/4" closed NEW!

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Kershaw Assisted Opening Spline Blackwash 8Cr13MoV Blade Framelock Folding Knife

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ALBATROSS Ball Bearing Assisted Open Pocket Folding Knife D2 Blade G10 Handle

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CAMPING KNIFE High Quality 8.5" Axis Lock Assisted Open Pocket Folding Knife

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Kershaw USA KnockOut Sandvik Assisted Opening Olive Green Knife 1870OLBLK

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KERSHAW 1660 LEEK assisted open linerlock knife, Several Less Common Variations

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KERSHAW NATRIX SUB FRAMELOCK SPEEDSAFE ASSISTED OPENING FOLDING KNIFE 7007OL

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Kershaw Scrambler 8Cr13MoV Assisted Opening Blackwash Blade Folding Pocket Knife

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Kershaw Blur Tanto Blackwash Assisted Opening Knife NEW IN BOX USA 1670TSTBW

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Kershaw Leek Flipper Speed Assisted Opening Orange Knife CLAM Pack 1660OR USA

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Kershaw Cryo G10 Assisted Open Pocket Knife Folder 1555G10X 8Cr13MoV 4 Way Clip

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KERSHAW "USA" - Olive Green LEEK Assisted SPEEDSAFE Knife w/ SAFETY LOCK 1660OL

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Kershaw Leek Stainless Assisted Opening Knife 1660 Ken Onion Design Plain Edge

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Kershaw Entropy 8Cr13MoV Blade Speedsafe Assisted Opening Folding Pocket Knife

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KERSHAW NATRIX SUB FRAMELOCK SPEEDSAFE ASSISTED OPENING FOLDING KNIFE 7007BLUBW

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Kershaw Leek 1660 Knife Knives Onion Plain Edge Blem blems New

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KERSHAW 1336BW HALOGEN SPEED SAFE ASSISTED OPENING KNIFE CARBON FIBER

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Kershaw 1620OL Scallion Olive Green Assisted Opening Plain Blade Pocket Knife

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1812 Kershaw Dividend Folding Pocket Knife Assisted Opening Plain Stonewashed

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Gerber Highbrow Compact Flat Sage FE Assisted Opening Knife 7Cr Steel 2.8” Blade

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Kershaw Leek RED Snap On 1660RAT Flipper Assisted Opening Knife USA 1660RATSO

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KERSHAW 1660 LEEK Speed-Safe assisted open linerlock knife USA

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KERSHAW - Al Mar AM-3 G-10 Spring Assist SPEEDSAFE A/O Flipper knife KAI 2335

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Kershaw - Halogen CARBON FIBER Spring Assisted FLIPPER Knife SPEEDSAFE KAI 1336

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KERSHAW "VEDDER" SPEED SAFE SPRING ASSISTED KNIFE RAZOR SHARP BLADE

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KERSHAW DIVIDEND DAMASCUS STEEL SPEEDSAFE ASSISTED FOLDING KNIFE 1812GRYDAM

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USMC Combat Master Assisted Open Kukri Huge Folding Pocket Knife UC3367 12 1/2"

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7.90 INCH GERBER HAUL SPRING ASSISTED KNIFE RAZOR SHARP BLADE COYOTE BROWN

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Kershaw Blur Tiger Stripe Tanto BDZ1 Steel Assisted Opening Knife USA 1670TTS

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Kershaw "usa" - M390 STEEL Link Spring Assist SPEEDSAFE Flipper knife 1776BLK

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Smith & Wesson M&P MAGIC Flipper Assisted Opening Knife with Safety Lock SWMP6B

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1600 Kershaw Chive NEW FLAG LOGO Knife plain Blade 3" frame lock New *Blem* A/O

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Kershaw Natrix Flipper Knife Blackwash Blk G10 7007BLKBW Assisted w/ Sheath

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Assisted Opening Knife Reviews

More About Assisted Opening Knives

A common source of confusion for new knife enthusiasts is the difference between a spring assisted knife and a switchblade knife. Even those who are familiar with pocket knives or fixed blade knives often don’t know the difference between a switchblade and an assisted knife. The confusion is easy to understand as in both cases the knife may seem to release from the handle on its own. But when you look more closely at the mechanisms which open each blade, you can quickly see the difference.

Although commonly confused with switchblade knives, a switchblade can be opened automatically simply with the push of a button, but the user of an assisted-opening knife must open it about one-quarter of the way (45°) before the mechanism opens the knife the rest of the way. The difference is important legally; because the blade does not open simply "by the push of a button or by force of gravity" the assisted-opening knife is typically not considered a switchblade, and may escape the restrictions applying to those in many places.

The switchblade, or automatic knife, has a button or a lever which releases the blade. The button or lever releases the tension held by a spring inside the knife handle. When the lever or button is pushed, the tension from the spring releases and launches the blade from the handle and into a locked position. Some switchblades release the blade from the side of the handle like a spring assisted or a folding knife, while others release out the front of handle (Out-the-Front or OTF).  There are very strict laws concerning the ownership and carry of automatic knives, and you should always check local regulations before purchasing to avoid problems.

The spring assisted knife, or assisted opening knife, doesn’t rely on a button or lever for opening. Instead, it uses a spring or torsion bar which doesn’t engage until the knife blade has opening momentum from another source. The best source is obviously human power engaging a thumb stud, thumb hole, thumb disc, or flipper, moving the blade forward until the spring or torsion bar engages and moves the blade open the rest of the way.

The simplest way to tell the difference is whether or not there is a button or lever. An assisted opening knife does not have a button or lever. It has some form of initializing action that requires human effort. Your thumb has to push on a flipper, a thumb stud, a thumb disc, or a thumb hole to start moving the blade. If there is a push button or a slide that releases the blade, that makes it an automatic.

The first assisted opening knife was designed by Blackie Collins in 1995 and was named the "Strut-and-Cut"; it was based on the strut of his Ducati motorcycle. A similar concept was developed three years later by knifemaker Ken Onion with Onion's idea based on a similar mechanism in his Harley Davidson motorcycle. Onion applied for a patent on his design in 1998.


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