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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SOG Fielder Assisted Open Folding Pocket Knife 5Cr15 G10 FF3002-CP 7.8" Open New

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

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Kershaw Scrambler 8Cr13MoV Assisted Opening Blackwash Blade Folding Pocket Knife

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Kershaw 1600 Chive Assisted Opening Ken Onion Knives Knife New *Blem*

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Kershaw Assisted Opening Spline Blackwash 8Cr13MoV Blade Framelock Folding Knife

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Kershaw Al Mar AM-4 Flipper Speed Assisted Opening G10 Knife BOX 2330

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Kershaw Entropy 8Cr13MoV Blade Speedsafe Assisted Opening Folding Pocket Knife

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Kershaw BlackWash Amplitude Assisted Open 8Cr13MoV Blade Folding Pocket Knife

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KERSHAW "USA" - Black LEEK Assisted SPEEDSAFE Knife w/ SAFETY LOCK 1660SWBLK New

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KERSHAW 1660BLKW LEEK BlackWash SpeedSafe assisted open linerlock knife USA NEW!

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KERSHAW "USA" - Black LEEK Assisted SPEEDSAFE Knife w/ SAFETY LOCK KS 1660CKT

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

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

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

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New Exclusive Kershaw Leek Folding Knife, BlackWash Blade w/ Blue Handle

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Kershaw Speedsafe Assisted Opening 8Cr13MoV Dagger Blade Folding Pocket Knife

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Gerber Highbrow Compact Assisted Opening Folding Knife Ambidextrous 8970619A

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Kershaw Blur Camo Handle Sandvik SpeedSafe Assisted Opening Knife USA 1670CAMO

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

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Kershaw Flourish Assisted Opening 8Cr13MoV Blade Folding Flipper Pocket Knife

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

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

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KERSHAW NATRIX SUB FRAMELOCK SPEEDSAFE ASSISTED OPENING FOLDING KNIFE 7007

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Kershaw 1620PUR Ken Onion Scallion Assisted Open Folding Knife

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Kershaw USA Tactical Assisted Open Knife - Ken Onion Leek 1660 Speedsafe

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

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Smith & Wesson S&W Knives Large M&P Assisted Open Folding Knife SWMP4LS

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Kershaw Leek Folding Knife, BlackWash Blade w/Red Handle 1660RDBW

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

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Kershaw Showtime SpeedSafe Assisted Open Folding Knife 1955 1955X

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10 Pcs LOT Assorted Spring Assisted Tactical Pocket Knife 10

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

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

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1670OLBLK KERSHAW BLUR Pocket Knife Speedsafe USA NEW *Blem* assisted opener

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Kershaw Link Blackwash Green Olive Flipper Assisted Opening Knife USA 1776OLBW

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Kershaw Scallion Blackwash Aluminum Handle Gray Folding Knife (1620GRYBW)

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SMITH & WESSON M&P DUAL ACTION SPRING ASSISTED & MANUAL CONVERTER KNIFE

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Kershaw - Halogen CARBON FIBER Spring Assisted FLIPPER Knife Blackwash 1336BW

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Kershaw Outright Blue PVD 8Cr13MoV Plain Edge Framelock Tactical Knife 8320

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Kershaw 1670BLK Blur Black Handle Plain Edge Assisted Open Folding Pocket Knife

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Kershaw 3960 Barstow Straight Assisted Blackwashed Folding Pocket Knife

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Kershaw Link Linerlock Folding Knife 3.25" 420HC Steel Blade Aluminum Handle

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Kershaw Natrix A/O Knife Gray G-10 Handle Black Stonewash Plain Edge 7007GRYBW

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SOG FLA1001 Flare Assisted Opening Pocket Knife Black Handle Satin Plain Edge

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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.