Idea: The Open Source Lock

[TOWCH]

Do any doors actually need the tail piece to be that long? Mine cound function with the tailpiece protruding 1/3 as much as it does.

[mh]

Do any doors actually need the tail piece to be that long? Mine cound function with the tailpiece protruding 1/3 as much as it does.

I'm not sure - I thought the tailpiece is the cam part in the middle of a double-euro or at the end of a half-euro-cylinder?

The length is usually available im 5-mm-steps on each side, to fits different door thicknesses.
And then you are supposed to mount a strong escutcheon plate around the front outside part, non-removable from the outside, that will fit exactly around the Euro profile, and nobody could grab the cylinder itself with tools.
Like this: http://www.haus-und-markt.de/Media/Arti ... 1140-2.jpg

If you look at the cylinder, the cam part is obviously the part with least material, e.g. because of the mounting screw hole.
To make that stronger, better material can be used there, as e.g. KESO and others do,
e.g.:
http://www.embvienna.com/Keso.jpg

These are the parts, but I found them too late
http://cgi.ebay.de/KESO-VERLANGERUNGSKO ... dZViewItem
or DOM:
http://www.sicherheitstechnik-wilke.de/ ... hloss1.jpg

Other manufacturers put parts around the cylinder that push against the escutcheon plate from the inside and therefore prevent pulling the cylinder out
http://www.schliessplan.de/menu_3/item_ ... system.gif
or through the cylinder
http://www.wagner-sicherheit.de/icon_se ... 0s/kzs.jpg

Or the put strong sheet metal to the sides of the cylinder, like Wilka:
http://www.wilka.de/menu_3/item_1/imgs/zylinder_vds.jpg

And then the actual cam can - instead of just being in the middle of the two sides - be made of two halves that -in a way- close around both sides of the cylinder, so that they can't be pulled apart. I don't find a picture of this, but I hope it makes sense.

Lots of ideas...

Cheers,
mh

[TOWCH]

Thanks. I'll see what I can dream up.

(Sorry, by tail peace I ment cam. )

[unjust]

so to back up a step, how do we deal with the 2 points of entry issue? mechanical and electronic attack?

i'm thinking that disabling the mechanical method unless the electronic fails. i.e. mech is phycisally seperated from latch if electronics are live. could be as simple as a battery backup for x time so that if power is cut, and emergency power is not restored w/in that time peroid, the battery drains and drops a pin into the lock tying the mechanical lock to the latch. the pin would be pulled back via electro magnet once power is restored.

attack on the physical lock would be pointless as it would be free to move unless the electronics are compromised. redundant electronics shoudl of course be in place such that when the operatin gcircuit fails due to whatever reason the physical lock is active.

[TOWCH]

I can't really add anything to the discussion of a mechanical override. They are traditionally a secondary means of operating latches or boltwork and not part of the lock itself. With the large number of electronic safe locks that do without, I think it's been demonstrated that a mechanical override is not a necessity or even desirable when security is the priority. If reliability, and a fail safe system take priority while convienence is desired then they have their uses. That said, there's no downside to making it an optional modification to a lock. I just wouldn't design a lock around it.

Here's what I came up with. There is no need for the two plugs of a double euro of our lock to move independantly of each other. We can take any double euro body, and replace the plugs and latch with one of our design that is the actual locking mechanism. The security against snapping comes from the two plugs threading together. Box threads could be used if necessary for strength.

The cam is either securely attatched to the outside diameter to the threaded end of the female plug and the plugs are restricted from rotating by electonically actuated sidebars, or the cam is free spinning on the outside diameter of the threaded end of the female plug, the plug's freely spin, and the cam can be secured from spinning and resultingly rotated upon successful authentication.

To add to pulling resistance, the "anti-shim" lips to the plug would be half of the length of a single plug.

Maybe some sort of ball bearing pull resistance could be added in place of the traditional retaining screw? You could drill an unthreaded hole the same diameter as the traditional retaining screw, and in the same place, and then have a threaded screw hole going from the interior face of the euro body all the way through to and intersecting with the retaining hole. You then put a cup faced grub screw into the in-most retaining screw hole of the door, put 2 ball bearings with diameters half the width of the euro inside the retaining in the euro, and pin then dived the bearings with a bolt driven down through the hole in the interior face of the lock. This bolt is made of steel to resist deformation, and has a de-threaded tip that is cupped on two sides to recieve the ball bearings. Then to finally secure it, you use a screw with a cup tip and secure the other ball bearing in the out-most retaining screw hole.

Did that all make sense?

[TOWCH]

Just had a thought. For the sidebar design, the interior face of the plug could have two cams running in behind the sidebars. When rotated, the cams allow or block retraction. You could even have radial sidebars all around the interior plug which have a negative inner plug sleeve which controls them all at once. Ball bearings would also work with a tech-9 esque sleeve.

To keep the outer plug from being unscrewed while the lock is locked, there would have to be a high shear strenth method of interlocking the two plugs once threaded together. I imagine this would be the weakest link in the whole design.

Don't get me started on drill resistance for the exterior plug and euro body.

[jhl]

i'm thinking that disabling the mechanical method unless the electronic fails. i.e. mech is phycisally seperated from latch if electronics are live. could be as simple as a battery backup for x time so that if power is cut, and emergency power is not restored w/in that time peroid, the battery drains and drops a pin into the lock tying the mechanical lock to the latch. the pin would be pulled back via electro magnet once power is restored.

Good idea, but unfortunately electromagnets eat way too much power to have on all the time - no matter how small you made it.

Also, if someone figures out a method to knock out the power, the mechanical system will become available, with its weaknesses - and with some sort of temporary knockout, that's not nearly as tamper-evident as someone having to take the whole door to pieces, either.

[jhl]

any path to the "outside world" will present a potential method for bypass, destruction, nullification or manipulation. a little sanding of the front lens of the light pipe can reduce the signal enough to make the lock stop functioning altogether.

A simply and correctly designed electronic lock is not "hackable"; with even a decent design exhaustive key search isn't possible either. Many cryptoless designs would work well in certain situations - if you're willing to ignore direct key compromise (just as a plasticine impression will kill most any high-security keyed system, too).

Sanding is very unlikely to cause problems with a light-pipe system; all it will do is diffuse the light - even if 80% is lost to back reflection somehow, it should still be easy to recover a rock-solid signal, especially at low rates.
Paint is a more serious issue; using a window material that is very hard to stick to would be very, very useful.


As for safe power input - an inductive coupling could provide a safer transfer method, but may require compromises in physical lock design. I can't imagine a non-ferrous frontplate would go down too well...

[mh]

As for safe power input - an inductive coupling could provide a safer transfer method, but may require compromises in physical lock design. I can't imagine a non-ferrous frontplate would go down too well...

Even if there's no emergency power input, I think it's still possible to design a usable system for everyday use - today's lithium batteries have a decent capacity, and the software would simply need to warn the user about a low battery condition early enough, then maybe at some point disable locking.
Of course in penalty mode (after 3 wrong keys), it should also go into "deep sleep" for some time and save energy, to avoid Denial-Of-Service attacks by simple tampering.

I still think it's a nice idea, and a doable one - we just would need some people with a mechanical background helping on the prototypes...

Cheers,
mh

[TOWCH]

Mine should be done by the end of the day I think.

[TOWCH]

Here she is: TOWCH Proposal Prototype V 0.5

http://i9.tinypic.com/34g9ekw.jpg
http://i15.tinypic.com/2istlbd.jpg
http://i16.tinypic.com/3142wc8.jpg
http://i17.tinypic.com/2uhuzp2.jpg
http://i17.tinypic.com/2rpti85.jpg
http://i19.tinypic.com/2rn9200.jpg
http://i13.tinypic.com/2upqvcw.jpg


I guess you could call this a prototype. It's not entirely finished as the cam needs filed flat and the front face of the lock hasn't been drill resisted. In a real "from scratch" version the lips on the plugs will be wider but I didn't want to try to bore out the euro case.

Had a nightmare when I realize my tapp wouldn't thread my shallow hole so I had to rechuck in the lathe and do finer inside thread work than I have ever done before. Was muttering to myself "I don't want to do this." over, and over, while I reground my smallest inside thread cutter so it would fit in the hole.


Didn't work very well. Shallow I think but the piece slipped in the chuck and I didn't want to try to resync the threads with the cutter. Better to have a mostly functional prototype-protype with weak threads than a nonfunctioning piece of scrap metal.

Improvements after the fact:
The front plug could have a groove cut in it and one of the pin stacks on the euro case bored out, threaded, and a ball bearing could be bound between the groove and a bolt.

For drill protection I'm planning on putting three ball bearings set in holes around the front plug. I'll dream up some other nasties, but drill protection is an after though IMO.

I want to resolve the issue of someone drilling out the fiber and binding the cam. Easy but not so secure solution is to put a steel tube all the way through the fiber keyway and use smaller fiber strands. Better solution IMO is to drill a hole at the shear line of the the cam, and have the electronics retract a blocking pin before turning the cam. Maybe a glass relocker over the front face of the lock?

[mh]

Wow! (more comments to follow once I understood it all )

[TOWCH]

Sorry, should have explained a bit better. It's changed a bit since the original idea.

The small plug inside the plug with the ball bearings is the "thumbturn" of the lock. I haven't drilled it or slotted it or whatever since I haven't decided on how to interface it with the electronics.

The groove in it is for the first ball bearing and is intended to keep it from being hammered out of the lock by whatever means someone dreams up. This ball bearing is dropped in through the hole on top of the euro case before the lock is locked.

The second ball bearing protrudes from the plug enough to wedge itself in to the pin stack hole from the original lock. When the cam is turned, the ball bearing is wedged between it hand the hole blocking both plugs and incidentally the cam from turning. When I've filed a flat spot on the cam, the ball bearing will have enough space to allow the plug to turn.

I'm leaning towards binding the cam to the works, and the two plugs together with a grub screw. Another factor I'm not decided on though.

I'll post measurements and drawings soon but I'll have to make them up myself. My notes are two sheets of paper with barely any comments on any of the numbers or math.

I don't have the skills or the patience necessary to make the final product from steel myself, so I'll probably end up using emachineshop for the final version if I ever make one.

[mh]

How would turning the cam from the outside work?

And how would the electronics/motor/magnet/whatever allow/prevent turning the cam? Is that by turning the 'thumbturn'?

[TOWCH]

The way I see it in my head, You press the key against the exterior face, I'll probably have 4 small holes surrounding the keyway, three for prongs from the key for rotating the plug, one with a pin inside it for depressing a switch on the key. Key does the blinky light echange, something pulls the monkey wrench out of the "thumbturn" shear line, stepper motor rotates "thumbturn", user turns key, both plugs rotate with cam securely attached in the middle, door unlocks.

I'll have to work out a way for the key to be retained until the plug is back in position. Probably use a ball bearing for that too. Maybe I'll just have two big prongs coming off the key, the bottom one looking a bit like the "thumbturn." Ball bearing working like the one retaining the "thumbturn" and the one blocking rotation at the same time.

I go sleep now.