Semi-pick proof lock

[Evan]

As for master keying, I just smell trouble when it comes to that. I do think this would be a good lock for residential use. There would be no need for it to be master keyed (even in a situation of a landlord owning several houses and wanting a master key for them all..I just find a key for each house to work better as far as security goes)

So to clarify your intended application for this "design" is standalone single dwelling residences only ?

That rules out quite a bit of the residential market as many places where three or more dwelling units are located in the same building the AHJ will require a lock box with keys for the fire department... In a complex with hundreds of units in a building not being able to master key the locks would be a cumbersome task to provide said access...

This is especially crucial in buildings protected by a fire alarm system as access to all parts of the building protected by the system is required...

~~ Evan

Hmm..well Its not to say that it can't be master keyed, though it might greatly affect security...although with those master pins in there, it could cause a greater chance of setting off the trap, which really isn't that huge of a problem. I'd just like to have it more difficult to pick (no master pins) so that there is a lower chance of the picker picking the lock to set off the trap, causing the oner to need to call a locksmith to reset the lock. I guess either way the trap will be set with picking and protecting the occupants from being intruded.

You do understand how fire departments operate when they encounter physical access barriers to which the keys fail to operate, don't you ?

The very best case scenario is that you will find several unusable and non-salvageable lock pieces on the floor near the door -- worst case you will find a mangled/destroyed lock still in the door AND the door and/or frame damaged to a point where it will need to be replaced...

So if master keying will increase the odds of triggering the trap and thus locking out all keys until the cylinder is serviced by a locksmith, I would NOT recommend it be used in a situation where you are providing keys to a fire department lock box and representing to the AHJ that said keys will provide access to the building in question if the design of the lock is not totally compatible with being master keyed... That definitely sounds like a recipe to ensure broken locks/doors in your future as well as the citation of violation for failure to provide a means of access from your AHJ...

~~ Evan

[xBMW M3 GTR]

...then simply don't have a master key setup...If these locks were installed on all doors in an apartment complex, then just have an owners copy of the key for each door.

[xBMW M3 GTR]

So from the looks of it, would you guys agree that this idea has been "perfected" (knowing theres no such thing as a perfect lock) or are there some other flaws in the design that need to be looked over. I did have an idea for a new trap pin, but I dont know if it would over complicate things...think of a spool pin, but the lower "ring" of the spool would be located in the center, and the lower half of the pin would just be a shaft as thin as the center of the spool. Looking at this thinner shaft it would be hard or even impossible to pick it onto any shear line. If picked to the. The center of the spool could be picked, but this would bind the plug and rings setting off the trap. made a few drawing. I'll try to get em uploaded later but for now off to class.

[xBMW M3 GTR]

After looking into it more, I found out that in total, there are 64 possible combinations as far as the order the 6 pins need to be picked to either the top or bottom shear line. (6 pins, 2 possible positions for each pin, 2^6=64 combinations)
for example U=Upper Shear Line L=Lower Shear Line
LLULUU
UUULUL
LLULUL
etc..

Im narrowing this down to 62 combinations though. A UUUUUU or LLLLLL combination would not be very practical. with 1 combination being correct out of 62, if the picker picks the lock they only have a 1.61% chance (rounded down) of their picking setup successfully opening the lock.

If i wanted to be a real jerk, this could be a 7 pin lock ...2^7=128 combinations, drop it to 126 by not making UUUUUUU and LLLLLLL possible combinations. This would give the picker a 0.79% chance (rounded down) of successfully picking the lock.

[landeroth]

this may be a misunderstanding, but i think you people have gone way overboard. i read all five pages and noticed one thing (and i'm blaming farmer freak). either i've missed something, or you've all taken this to where it doesn't matter which shearline is used, a trap pin will catch from the side, not the area the key pin is in... ie, the lock would be impossible to open even with the key. this is based off of farmer freak's drawings. if you have it where a trap pin sets from the side if the outer plug is turned, the inner plug must be the right one to use. if you have trap pins going from the inner plug into the outer plug if the outer plug isn't turned, then both must turn. however, it seems to have progressed to where it locks no matter which one is turned... i admit, it seems like really high security to make it where it locks in place no matter what you do, but what happens when it is so secure the key can't open it anymore? either that i seriously misunderstand the design concept.

[landeroth]

nevermind... didn't notice the outer trap pin was removed in the later drawings. now i feel kinda stupid (it's ok, i'm used to the feeling)

[MrScruff]

nevermind... didn't notice the outer trap pin was removed in the later drawings. now i feel kinda stupid (it's ok, i'm used to the feeling)

I'd rephrase it to "now I feel slightly more educated".

Nothing wrong with being wrong, just so long as you learn from it.

[kwoswalt99-]

Hello,
Here is an idea that I think would belong in this thread, and relates to this post

I'm having a little trouble picturing how it would work exactly although I do think I understand what you're saying. Do you mind making a quick sketch of it in MS paint or something just as a reference example?

Sure thing, I uh, didn't spend a lot of time on these. And I didn't bother drawing the serrated pins.

This top picture is basically your set up. If it is turned on the bottom shear line it will turn freely and won't lock up. But will lock up if the outer sleeve gets turned.


To change the shear line so now the top shear line is the correct one we simply need to put a trap pin (shorter in length) into the plug and leave the one in the housing out. With this set up, if the plug turned without the outer sleeve, the trap pin will lock the plug to the outer sleeve, which would be held in place by the regular driver pin at that point.


This next picture shows that there are 6 of these outer sleeves, one per pin chamber.


mh, if this were to be set up slightly differently and not set up to permanently lock up the plug/sleeves. I believe it could be set up as a basic commit then authenticate system.

This idea is kinda like a commit then authenticate pin tumbler, except that it doesn't use trap pins. The very outer sleeve is the one that is connected to an actuator, kind of like in the rivers lock. The middle sleeve is stationary. I am not totally sure, but I believe the reason why locks with two shearlines can be picked is because when they are tensioned, the pins tension the outer shearline. In this one, the outer shearline is only tensioned, when the pins are set to any combination on the lower shearline, and when the core is rotated until the little arm comes in contact with the outer sleeve. I don't know how bumping would work on this lock. One problem I see though is that when relocking it, the shearlines wouldn't line up. This could be overcome, but I didn't put it in this drawing. I also didn't draw it right, in this drawing you might be able to use a comb, and raise all the pins until all of the wafers are at the outer shearline, but it wouldn't be this way in reality. Not that this will ever be a reality. It seems a little impractical, but I find it interesting. Maybe it could be used in a mogul cylinder.

[kwoswalt99-]

Oh, I just remembered that I had a similar idea that might be more practical. This could be done with a tubular lock, and could fit in a euro cylinder. I will post a drawing later.

[FarmerFreak]

Oh, I just remembered that I had a similar idea that might be more practical. This could be done with a tubular lock, and could fit in a euro cylinder. I will post a drawing later.

Making your idea in a tubar lock makes more sense. I wasn't sure how you were going to make the center sleeve stationary. But that's doable in a tubular lock.

Also, you should check out this thread viewtopic.php?f=25&t=46768

[kwoswalt99-]

Well crap I didn't see that. Or maybe I did and forgot, oh well, I guess I better post some more ideas.