Spyderco Forums

Hello all of my fellow forum folks. I hope I don't seem ignorant with this question: Can you all please explain to me the basics of how the Compression Lock works/operates, especially the variant used on Spyderco folders? I ask because I am really looking forward to the upcoming Spyderco Caribbean and it is a compression lock-knife. I was looking at the pictures available so far, and I do not see how one closes a compression lock. I am not at all familiar with it. Thank you all ahead of time for explaining it.

I did find this:

COMPRESSION LOCK
A lock mechanism that uses a leaf-like spring from a split liner in the handle to wedge laterally between a ramp on the blade tang and the stop pin (or anvil pin). Developed and patented by Spyderco, it provides extreme lock strength and ease of use.

From the Spyderco website.

Basically it's an upside-down liner lock SEF :D

farnorthdan wrote:Basically it's an upside-down liner lock SEF :D

I got my first one today and that's what I thought when I looked at it :)

farnorthdan wrote:Basically it's an upside-down liner lock SEF :D

Thank you Dan, that helps me "get it" now! Appreciated greatly :)

The geometry is like an upside-down liner lock. A liner lock uses the length of the liner pushing against a flat spot on the blade tang to resist blade rotation. The compression lock puts a thinner end of the liner in between a flat spot on the tang and the stop-pin through the top of the handle. The liner lock design is somewhat sensitive to the length vs. thickness of the liner to resist blade closing. The liner can buckle or it can slip and the blade can close. The compression lock puts a much shorter piece of metal in there and it is less likely to buckle, and I think it isn't angled as much as a liner lock so there is probably less chance of the locking piece being pushed out of the way by force on the blade.

If you have a PM2 you can look down into the top of the handle and see how the pieces interact. If you don't have a PM2 then you can google search images for compression lock and find diagrams of how it works or disassembled knife photos to see what the pieces look like.

Yeah more or less at least in how it unlocks it functions like a liner lock on top that you operate with your index finger instead of your thumb. I like it because it allows me to swing the blade shut in one fluid motion while my fingers are out of the way.

The only thing it has in common with a liner lock is that it uses a liner. Other than that it actually functions much more like a axis/cbbl/bolt action lock. It is really a hybrid between the two styles.

A liner lock has a force vector that runs the length of the handle. The liner moves over and engages a ramp and when you try to close the knife the force pushes straight down the lock bar. That means that the modes of failure are likely to be either the lock bar bending or slipping off the ramp.

A compression lock has a force vector perpendicular to the handle of the knife. The liner moves over and a tab engages the ramp by wedging between the ramp and the stop pin. When you try to close the knife the tab that has wedged itself in there is squeezed between the ramp and the stop pin. The modes of failure with it are likely to be either the liner slipping off the ramp, the tab being crushed or the stop pin being blown out of the handle. Much like the axis lock wedges a horizontal bar into a ramp, the bolt lock wedges an inline bar into a ramp and the cbbl wedges a bb into a ramp the compression lock wedges a tab into a ramp. They all wedge an object between a ramp and a solid object above the ramp.

Unlike the liner lock which puts no force on the stop pin when trying to close the knife all these other locks do and all these other locks put the force upward perpendicular to the length of the knife. When you try to close a compression lock there is no force put on the length of the liner. Just on that tab.

Like the liner lock the comp lock lacks a bias towards closing which the bolt/axis/cbbl all have and instead relies on a detent ball. Besides the use of a liner that is the other thing it shares in common with the liner lock.

All I know is that it’s the greatest non-auto locking mechanism known to man.

Hi SEF,'
Actually the liner lock and the compression lock are completely different in principle and mechanics. Look closely at Killer's explanation.

sal

It's incredibly easy to close. Here is a 10 second video:

https://streamable.com/ftcwj

SpyderEdgeForever wrote:Can you all please explain to me the basics of how the Compression Lock works/operates?

SEF,

You owe Darby a box of beer! :p

bearfacedkiller wrote:The only thing it has in common with a liner lock is that it uses a liner. Other than that it actually functions much more like a axis/cbbl/bolt action lock. It is really a hybrid between the two styles.

A liner lock has a force vector that runs the length of the handle. The liner moves over and engages a ramp and when you try to close the knife the force pushes straight down the lock bar. That means that the modes of failure are likely to be either the lock bar bending or slipping off the ramp.

A compression lock has a force vector perpendicular to the handle of the knife. The liner moves over and a tab engages the ramp by wedging between the ramp and the stop pin. When you try to close the knife the tab that has wedged itself in there is squeezed between the ramp and the stop pin. The modes of failure with it are likely to be either the liner slipping off the ramp, the tab being crushed or the stop pin being blown out of the handle. Much like the axis lock wedges a horizontal bar into a ramp, the bolt lock wedges an inline bar into a ramp and the cbbl wedges a bb into a ramp the compression lock wedges a tab into a ramp. They all wedge an object between a ramp and a solid object above the ramp.

Unlike the liner lock which puts no force on the stop pin when trying to close the knife all these other locks do and all these other locks put the force upward perpendicular to the length of the knife. When you try to close a compression lock there is no force put on the length of the liner. Just on that tab.

Like the liner lock the comp lock lacks a bias towards closing which the bolt/axis/cbbl all have and instead relies on a detent ball. Besides the use of a liner that is the other thing it shares in common with the liner lock.

Well stated, sir! I was preparing to type out a long reply. You saved me the trouble and did a better job than I would have. I love the compression lock, it's my favorite locking mechanism.

Bloke wrote:SEF,

You owe Darby a box of beer! :p

:D How many beers in a box?

anycal wrote:

Bloke wrote:SEF,

You owe Darby a box of beer! :p

:D How many beers in a box?

Ah, hahaha! :)

24 x 375ml stubbies or 12 x 750ml longnecks! :D

Thanks guys. If it helped I am happy.

bdblue's description was good. I just geeked out and went into more detail. I am sure you have all noticed by now I am long winded. Also, the other's were all correct that from the outside the interface is like a reversed liner lock. You do still operate it by pushing a liner out of the way but on top. All good answers here and as always a super helpful bunch. :)

I will never turn down a free beer.

The compression lock is explained very well above. Here is a good visual that shows the difference with cut-aways. The lock explanations start at 9:30 https://youtu.be/1ddOdONCCqU

Vivi wrote:It's incredibly easy to close. Here is a 10 second video:

https://streamable.com/ftcwj

:cool: :thumbup:

Or one can disengage the lock using thumb with forefinger in the Spydiehole. It becomes very similar to closing a lockback.

That video is great. I don't know how I missed that one until now. That sure could have saved me a bunch of typing. :)

anagarika wrote:

Vivi wrote:It's incredibly easy to close. Here is a 10 second video:

https://streamable.com/ftcwj

:cool: :thumbup:

Or one can disengage the lock using thumb with forefinger in the Spydiehole. It becomes very similar to closing a lockback.

Yep, that's what I do when I use a compression lock knife with my left hand.

So I know that the Compression Lock is patented, but who designed it? Someone at Spyderco, or did they license it or something? These were questions that drove me to the US Patent Office database, which I've spent considerable time on for a master's degree course a few years ago (patent troll research). You'd be surprised over the really interesting, unique ideas companies have. If there's even a chance they'll want to put out a product or even pursue a product design, they'll apply for a patent. Spyderco has some out there in similar fashion.

It looks like Spyderco has 127 patents, design and function. Not sure about active vs inactive patents.

Folding knife with compression locking mechanism:
http://patft.uspto.gov/netacgi/nph-Pars ... S=Spyderco

Here are some other interesting ones:

Handles for a Butterfly knife:
http://patft.uspto.gov/netacgi/nph-Pars ... S=Spyderco

Hand held multi-tool:
http://patft.uspto.gov/netacgi/nph-Pars ... S=Spyderco

Basically a single piece Sharpmaker?:
http://patft.uspto.gov/netacgi/nph-Pars ... S=Spyderco

A diamond shaped SpydieHole!:
http://patft.uspto.gov/netacgi/nph-Pars ... S=Spyderco