The vast majority of mechanical locks in use today are of the "pin and tumbler" variety.

They have an outer cylinder, an inner cylinder, and pins which are supposed to prevent these two cylinders from rotating relative to one another unless the correct key is inserted.

The biggest weakness of the pin and tumbler lock is "picking", where these two cylinders are twisted relative to one another using some sort of tensioning tool, and then a lockpick is inserted into the keyhole to move around the pins.

This idea is prevent picking by preventing tensioning.

Tensioning in a common lock is possible because the outer cylinder is usually incorporated into the lock housing, while the inner cylinder is rotated by the key. This means that a would be thief has physical access to both cylinders.

In my idea, this is reversed: the inner cylinder is incorporated into the lock housing, and is unable to rotate, while the outer cylinder is what rotates and moves the deadbolt, or allows/prevents the latch from moving.

The outer cylinder is completely hidden and protected inside of the lock housing, and a would-be thief has no direct access to it, and as you will see, no indirect access either.

With only access to one of the cylinders, tension cannot be applied, and the lock cannot be picked.

Now, I'm sure you are wonder, how does the lock actually open?

First, the TL;DR version: Push the key into the lock, the key pushes on a rod, when the rod is fully pushed in by the key, the lock magically changes from locked to unlocked, or vice versa.

Next, the expanded version:

The rod inside of the lock's keyway has two springs attached to it; a lightweight spring to reset the rod and push out the key, and a stiff spring to drive some gears.

When the rod is pressed all the way into the lock by the key, the stiff spring detaches from the rod, connects to the planet gear of an epicyclic gear, and expands, rotating the planet gear.

When the stiff spring is when fully extended, it disconnects from the planet gear, and reconnects to the rod.

The ring gear of the epicyclic gear is connected to the outer cylinder of lock and also to the deadbolt or whatever locks/unlocks the lock.

The sun gear of the epicyclic gear rotates a dampener or dashpot of some sort.

If the correct key is in the lock then the energy from the expanding mainspring quickly moves through the epicycle gear into the ring gear, and successfully locks or unlocks the lock.

After a success, lock becomes ready the instant the key is fully removed.

If an incorrect key is in the lock, then the energy from expanding main spring moves through the epicycle gear into the sun gear, and spins the dashpot, putting the spring into to it's "ready try again" state within several seconds.

After a failure, not only does the key need to be removed for the lock to be ready, but the main spring needs to be fully expanded, however long that takes.

This idea does not prevent lock bumping, nor the use of tryout keys, but should *significantly* increase the time between one attempt and the next.

This concept should work with pin tumbler locks, wafer tumbler locks, and disc detainer locks.

Downsides: Your friendly neighborhood locksmith might need to destroy the lock if you lose your keys and need to open the lock.
-- goldbb, Mar 15 2021

You've put a lot of thought into this, haven't you?
-- UnaBubba, Mar 15 2021


What is the energy input into the system? You are extracting a fair amount of energy with your damper and gearing and springs.
-- pocmloc, Mar 15 2021


Where there is complexity , unseen failure points are sure to lurk. Given enough monkeying, one might leap out.

What stood out to me was that a spring, on a key push, does all this gearing mechanism motion. I would have thought some winding would have been involved.

My guess is this lock won't be one for constant use. Only the most secretive of items to be left in the dark.
-- wjt, Mar 15 2021


//The rod inside of the lock's keyway has two springs attached to it; a lightweight spring to reset the rod and push out the key, and a stiff spring to drive some gears.//

Fine.

//When the rod is pressed all the way into the lock by the key, the stiff spring detaches from the rod, connects to the planet gear of an epicyclic gear, and expands, rotating the planet gear.//

What?
I think I need a diagram of this, and the mechanism following that.

Here are some things I'm wondering about:
What is the difference between keys?
You say "Push the key into the lock". Just push it straight in? No twisting?
You say the key pushes on 'a rod'. A /single/ rod?
-- Loris, Mar 15 2021


A puff of smoke, guided by the judicious use of a mirror, and the lock will spring open. My money's on the lock pickers. I've seen them opening every unpickable lock that exists. Check YouTube for examples. I do like the reversal of mechanism idea, so it's a thumbs up from me.
-- xenzag, Mar 15 2021


//Downsides: Your friendly neighborhood locksmith might need to destroy the lock if you lose your keys//

This goes one of two ways. Either it's cheaper to destroy the lock rather than pick it, or, there's an easier way around it. In my area, I've seen three main methods: 1. An inflatable pillow, this bends the door frame slightly. Terrifying really, that an $8 item can open practically all doors in my area, simply as a by-product of flexible wooden construction. 2. Drill through the lock, it looks like some kind of carbide end-mill on a reasonably high- end battery drill. 3. If that doesn't work, they drill through the door and then cut around with a sawzall. Then replace the door.

I live around a lot of forgetful student types, and picking seems to not be a time-efficient method used by any locksmith I've seen. They could just be an inelegant lot however.
-- bs0u0155, Mar 15 2021


It reads as if the difference between the correct key and an incorrect key is the quantity of energy passed to the main spring. Is this correct, or is there also some qualitative difference, such as the direction of some force vector somewhere?

I'm asking because, if the only variable is quantity of energy, then the picker's problem is reduced to that of identifying the correct value of just one variable - and if there's any subtle hint which distinguishes between "that was too much force" and "that was too little force", then that will help the picker a lot. But maybe there's some other factor in play?
-- pertinax, Mar 15 2021



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