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 USA Leek BLACKWASH 1660BLKW 1660BWWM Speed Assisted Opening Knife CLAM

$39.95
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Kershaw Speed Bump Speed Flipper Assisted Opening Stud Lock G10 Knife 1595G10

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

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Kershaw USA Leek Speed Spring Assisted Opening Sandvik Blade Pocket Knife 1660

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KERSHAW Black DIVIDEND Assisted Stonewash Straight Folding POCKET Knife! 1812

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

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

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Kershaw USA Tactical Blur Blackwash Pocket Folder Assisted Opening Knife 1670BW

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

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Kershaw LARGE Cryo II Hinderer BLACK Blade Folder Assisted Opening Knife 1556BLK

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

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

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MTECH USMC TACTICAL FOLDING POCKET KNIFE Military Combat Assisted Blade MARINES

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KERSHAW Gray Handle BLACKWASH LINK Assisted Straight Folding Knife! 1776GRYBW

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

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KERSHAW Gray DIVIDEND Assisted Straight STONEWASH Folding Pocket Knife! 1812GRY

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

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

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KERSHAW Black CHIVE Straight Assisted DAMASCUS Folding Pocket Knife! 1600DAMBK

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Kershaw USA Blur Tanto Blackwash Assisted Opening Folder Knife BOX 1670TSTBW

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KERSHAW Blue LINK Assisted Blackwash Straight Folding POCKET Knife New! 1776NBBW

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9" Spring Assisted Open Folding Pocket Knife Karambit Claw Combat Tactical New

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

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Kershaw USA Blur Tiger Stripe OLIVE Hdl Sandvik Assisted Opening Knife 1670OLTS

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Kershaw Cryo II Hinderer 2 - 1556TI or 1555TI or 1556BW Assisted Opening Knife

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BLACK SPRING ASSISTED OPEN POCKET KNIFE | 8.75" Folding Tactical Tanto Blade NEW

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Kershaw Cryo II Hinderer 2 - 1556TI or 1555TI or 1556BW Assisted Opening Knife

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Kershaw - Flourish CARBON FIBER & G-10 Spring Assist Flipper Knife A/O KAI 3935

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BLACK SPRING TACTICAL RESCUE Assisted Open Folding Blade Pocket Knife M-TECH USA

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

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KERSHAW Black AM-3 Straight 8Cr13MoV ASSISTED Folding Pocket Knife New! 2335

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KERSHAW Black Assisted LEEK Straight Damascus Steel FOLDING Knife! 1660DAMBK

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8" Knife Spring Assisted Pocket Open Folding Tactical Alum Handle WOLF CHROM

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Kershaw Showtime SpeedSafe Assisted Open Folding Knife 1955 1955X

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KERSHAW "USA" - BLUR BLACK spring assist SPEEDSAFE knife Ken Onion KAI 1670BLK

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Gerber Instant Assisted Open Pocket Knife Plunge Lock G10 7Cr17 30-000436 New

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M390 STEEL Limited-Edition Sprint Run - KERSHAW Dividend ASSISTED Knife 1812BLK

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Kershaw CRYO II 2 1556 TI Hinderer Speedsafe Flipper Knife - FAST SHIPPING!!

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Kershaw 1776GRYDAM Link A/O Folding Knife Blade Gray Aluminum Damascus Steel

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8" Knife Spring Assisted Pocket Open Folding Tactical Alum Handle WOLF Rainbow

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KERSHAW "USA" - Carbon Fiber LEEK CPM-154 Spring Assisted SPEEDSAFE Knife 1660CF

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

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KERSHAW Gray DIVIDEND Straight Assisted DAMASCUS Folding Pocket Knife 1812GRYDAM

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

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

$25.95
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NEW COLD STEEL G-10 SWIFT I Assisted Straight Folding CTS-XHP Knife 22A

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MTECH MARINES TACTICAL USMC ASSISTED KNIFE Folding Pocket Military Camo Blade

$611.95
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KERSHAW Stainless Steel CHIVE Assisted Damascus Folding Pocket Knife! 1600DAM

$55.14
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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.