Double Keyed Lock with geared cylinders?

[FFCrash]

I used to have an old Cold-war era Soviet lock that took 2 keys to open, with each key being differently keyed. The problem was that the two cylinders could turn independent, and so you could pick one, and then the other.(There's one on ebay right now that is similar)

What if you made a lock similar that had both cylinders geared so that they had to be turned together. In theory, you could make the gearing tight enough tolerance that a tension wrench wouldn't be able to bind/set the pins unless you did both cylinders simultaneously, and then you'd have to know both cylinders were physically connected beforehand. In addition, you could make the cylinders rotate both directions, but only unlock in one. Then you'd also have to know which way the cylinders turned properly to unlock in order to try and pick them.

I think the trick would be:
a) make the connecting gears high tooth count, spiral drive gears - this eliminates slop in the gearing, makes them very tight tolerance, and makes them longer wearing.

b) make the gears physically engage a locking mechanism that prevents cylinder movement until the key is inserted to push the locking mechanism away
i.e. any given pin on both cylinders could be connected to a toothed arm that engages each gear. the gearing wouldn't even have to be at the back end of the cylinder . You could machine the teeth into the cylinder at the key end (or in theory, at both ends), which might prevent a tension wrench from even functioning.

Thoughts?

[tecnovist]

if you had 2 sets of pins this would have the same effect and have a split barrel like the barrel was cut on half round the middal - then how would it be tensioned up to pic - along woth threaded spools and pins - tecnovist -

[FFCrash]

having two sets of pins in one cylinder isn't quite the same effect. The purpose for having two cylinders is the physical difficulty for one person to pick two separate locks simultaneously with just two hands.

[FarmerFreak]

If tensioning either cylinder tensions both cylinders, then only one hand is needed to tension both cylinders.. Leaving the second hand to single pin pick all of the pins.

i.e. any given pin on both cylinders could be connected to a toothed arm that engages each gear. the gearing wouldn't even have to be at the back end of the cylinder . You could machine the teeth into the cylinder at the key end (or in theory, at both ends), which might prevent a tension wrench from even functioning.

I'm not sure what you are saying here, attaching a gear to the side of a pin? To do what exactly? You may need to draw a picture to clarify things.

[tecnovist]

have a split barrel like if the barrel was cut on half round the middal even in 3 places how would it beTensioned then

[FarmerFreak]

Technovist I have the same problem with your idea that I have with FFcrash's idea. I don't know exactly what your ideas are.. A crude drawing would likely fix that problem, and lead to a better discussion.

how would it beTensioned then

You have a serious logistical problem to overcome here. If a lock cannot be tensioned, then how would a key open it? Remember, the key can't tension anything either.. If the key does tension something, then that something can be tensioned!

[mh]

have a split barrel like if the barrel was cut on half round the middal even in 3 places how would it beTensioned then

If you design a lock with 3 plugs behind each other, where the key goes through all 3, I will tension only the last plug (with a tool that has a flat tip on a long round stick) and pick only the last plug.

[FFCrash]

I'm not sure what you are saying here.. You may need to draw a picture to clarify things.

Yeah, I need to figure out how to draw the image in my head.

I'm still trying to figure out how to draw the design. It would be essentially a hidden pin that intentionally binds the gearing around the plug before any of the rest of the pinstacks can be set.

The gear pin would be lifted out of place by having a specific pinstack at the correct depth via the key, prior to turning the plug. Due to the gearing interlocking both plugs, attempting to lift all the pins on one side to unlock the gear pin would not allow the plug to rotate due to the second plug still being locked in place by its gear pin. If you unlocked both gear pins and rotated both cylinders to start properly setting the pinstacks, the gear pin could drop down into the gearing and lock the cylinder again.

If you made the holes for the pinsets slightly different sizes, you could reduce the chance of tactile feedback from the pins catching the sheer line once the binding pin is lifted on one side.
It's very difficult to set pins if there's no tactile feedback from the pins you can access, and the binding pin is not directly physically accessible.

Because the locking pin can engage gearing all the way around the cylinder, you couldn't just overset it once to lift it out of the way, you would have to keep the specific driver pin set all the way through the rotation.

This would probably be one the most expensive padlocks ever made...

[tecnovist]

i have been nutting this out for some time OK i may not have it - - and it would need to be netter than this - but if you diced the barral into say 3 bits - the key would still reach the the 3 bits _ but would a tenshion tool be able to do the 3 at once - ok you would need some way of stoping the out side diced barral from fulling out - but the one in the middal could flout - hope that quick reply helps a pic would help i will see what i can do and take a photo of one thanks tecnovist

[FarmerFreak]

i have been nutting this out for some time OK i may not have it - - and it would need to be netter than this - but if you diced the barral into say 3 bits - the key would still reach the the 3 bits _ but would a tenshion tool be able to do the 3 at once - ok you would need some way of stoping the out side diced barral from fulling out - but the one in the middal could flout - hope that quick reply helps a pic would help i will see what i can do and take a photo of one thanks tecnovist

have a split barrel like if the barrel was cut on half round the middal even in 3 places how would it beTensioned then

If you design a lock with 3 plugs behind each other, where the key goes through all 3, I will tension only the last plug (with a tool that has a flat tip on a long round stick) and pick only the last plug.

FYI, it's been done. Mainly for fun though, as it isn't exactly the most pick resistant idea.. viewtopic.php?f=9&t=44569&start=0 Okay, it only has 2 plugs instead of 3, but that wouldn't change much.

[tecnovist]

FarmerFreak » thanks for the link

by mh » Sat Jun 22, 2013 11:44 am
Thanks i understand after reading you post - all one would need to pick in the back part of the barrel - turn it and the lock would open

-In an attempt to make the lock pick prof this makes the lock more complex adding more to the price - its an interesting thing to be working on

[C locked]

I'd use a dual cam on each cylinder. 1 geared. And 1 a cam with a clutched mechanism to apply a pressure to the locking bar which the geared cam engages. Think the clutch mechanism from simplex 1000. ...pick 1 cylinder. The clutched mechanism disengages with the locking bar. Due to the 2 cams not turning at the same time. ...it works in my head.

[tecnovist]

Its been a while ,, you could have like a crank in stead of gears connecting the 2 barrals ,, & if you had a diced barrel , but connected by a rod/pin or lug with a lose slot in the next diced bit ,, so as that dice barrel could not turn enouth to unlock the bolt / staple ,,not with out picking the next one & if one was spring loaded it would pop back ,,OK It would be micro engineering ,, so its one thing nutting stuff out but making it & getting it to work ,,

[tecnovist]

The other thing is ,, if the 2 barrels were connected by a crank or gears ,, you would need a key in each one at the same time to turn the barrels ,, to onlock the lock ,,

[smokingman]

If you make a tension wrench as long as the key you will reach all parts of the plug at the same time, I have some like this for certain locks that have some piece or pin at the rear of the plug to turn or lift.