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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Kershaw Link Assisted Opening 420HC Tanto Linerlock Folding Knife 1776T

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

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Kershaw LARGE Cryo II Tanto Blackwash Speed Assisted Opening Knife 1556TBW

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

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KERSHAW black BLUR ASSISTED opening Knife 1670TBLKST tactical tanto tip. Blem

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Smith & Wesson M&P Large Design Assisted Opening Knife Glass Breaker SWMP9BTS

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Kershaw 1660 Leek Ken Onion Plain Edge SpeedSafe Assisted Opening Knife NIB

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Kershaw Link 420HC Assisted Opening Blue Handle Tactical Knife 1776NBBW New!

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Smith & Wesson M&P LARGE MAGIC Assisted Opening Knife Glass Breaker SWMP9BS

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1600 Kershaw Chive Knife plain Blade 3" frame lock New *Blem* ass

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

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12" GIANT TACTICAL Assisted Open Pocket Knife CLEAVER RAZOR FOLDING Blade NEW

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Kershaw Al Mar AM-3 Flipper Speed Assisted Opening G10 Knife CLAM Pack 2335 AM3

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1776 Kershaw Link pocket knife assisted opening New Blem* Made in USA

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

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

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12" GIANT TACTICAL Assisted Open Pocket Knife CLEAVER RAZOR FOLDING Blade NEW

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Kershaw USA Tactical Blur Stonewashed Navy Blue Assisted Opening Knife 1670NBSW

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Kershaw USA Leek BLACKWASH 1660BLKW Speed Assisted Opening Knife CLAM Pack

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KERSHAW - Black CLASH Spring Assist SPEEDSAFE Knife Ken Onion kai KS 1605CKTST

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Spring Assist CERAMIC blade CARBON FIBER & Titanium pocket knife Timberline 8018

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Kershaw 1881 Titanium Carbo-Nitride ERIS Straight Assisted Opening Folding Knife

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Kershaw LOT OF 3 Neck Knife & 2 Assisted Open Pocket Knives 3PC Speedsafe

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1776TGRYBW Kershaw Link Tanto Point pocket knife assisted opening New Blem USA

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Kershaw NATRIX Black Flipper Assisted Opening Folder Knife BOX 7007BLK

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

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Kershaw Speed Bump Speed Flipper Assisted Opening Stud Lock G10 Knife 1595G10

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Kershaw USA Tactical Blur Black Tanto Sandvik Assisted Opening Knife 1670TBLKST

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KERSHAW "USA" - BLUR Tanto BLACKWASH PS spring assist SPEEDSAFE knife 1670TSTBW

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Kershaw Al Mar AM-4 Flipper Speed Assisted Opening G10 Green Olive Knife 2330GRN

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Smith&Wesson M&P Spring Assisted Open Black Tactical Folding Pocket Knife MP4L

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Kershaw Clash Black Flipper Assisted Opening Part Serr Knife NEW CLAM 1605CKTST

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Kershaw "usa" - M390 Dividend Spring Assist Speedsafe FLIPPER knife KAI 1812BLK

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KERSHAW usa - LINK Blackwash TANTO 1776TGRYBW spring assist A/O FLIPPER knife

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Kershaw 1620C Camo Scallion Ken Onion Plain Edge Assisted opening Knife NIB

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1660ST Kershaw Leek Knife silver combo Blade New *Blem* assisted opener

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Smith & Wesson M&P Spring Assisted Opening Tactical Folding Pocket Knife SWMP4LS

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KERSHAW 1660ORX LEEK Orange Speed-Safe assisted opening linerlock knife USA NEW!

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Kershaw 1605CKTSTX Clash Assisted Opening Black Serrated Folding Pocket Knife

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Kershaw Al Mar AM-3 Flipper Speed Assisted Opening Knife 2335GRN AM3 OLIVE

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New Kershaw Leek Folding Knife, Black Blade w/ Navy Blue Handle 1660NBBLK

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Kershaw - SPEED BUMP Spring Assist UNIQUE LOCK knife DISCONTINUED model 1595 G10

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SOG Flash II Assisted Folding Knife TFSAT8-CP - Black TiNi 3.5" Tanto Straight

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

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Kershaw Grid 8Cr13MoV Plain Edge Assisted Opening Tactical Folding Knife 2200

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

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Kershaw 2335 Al Mar AM-3 8Cr13MoV Plain Edge Assisted Open Framelock Knife

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# 3871WM Kershaw Amplitude 3.25 pocket knife Assisted Opener knives Rexford 3871

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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.