Improving the common pin tumbler

[LodeRunner]

Hello everyone. Long time lurker, first time poster. I'm still a long way from being proficient at any picking or bypassing technique (though I'm making good progress thanks to the cutaway lock and pinning kit I got from Varjeal's Toolshed), so I don't really have anything to contribute in regards to techniques, but I had an idea for improving the ubiquitous 5-pin tumbler lock.

There are a lot of high-security locks out there, but they generally require expensive manufacturing (close tolerances) and/or special keys that can't be duplicated by your local Home Depot or Wal-Mart. From a commercial standpoint, the ideal high security pin tumbler should cost only somewhat more than your basic kwikset and it should use the same standard house key (remember, I said from a COMMERCIAL standpoint.)

My idea is to create a duplicate set of driver pins located about halfway in-between the plug's resting position and the position where it is unlocked. These extra driver pins will be unique in that they are notched. If the door is opened with the proper key, the pins stay up out of the plug (the sheer line is already met) and the lock opens normally. If any of the driver pins are allowed to fall down, a spring-loaded bar snaps out into the notches, preventing the pin from being moved by any means and effectively disabling the lock. (Though perhaps there can be a way to reset it from the other side using a special tool.)

The second set of driver pins cannot be bypassed by traditional picking, raking, bumping or pick gun. They can, however, be bypassed by a plug spinner. It took me a good 45 minutes of pondering this attack before I figured out a solution. This may be a little hard to visualize and I suck at drawing, so bear with me here:

Just beyond the keyway, the plug will have a double lip extending into the housing (is this the right term?) In-between these two lips will be a lightweight pin and spring attached to the plug. It will look kind of like this:

#=housing
*=plug
@=lightweight spring
I=lightweight pin

(side view)
###########
###########
###########
######* II*##
######* II*##
*********II****
[keyway]*@@***
**************

The plug's double lip has a gap in it right around the lightweight pin. The edges are sharply beveled.

L=the double-lipped part of the plug
K=keyway
-=empty space

(straight-on view)
######
######
LL--I--LLL
***@***
***K***

The lightweight pin's progress will be unhindered up until a certain point--the exact same point that the key pins meet the secondary (notched) driver pins. At this point, the lightweight pin is pointing straight up and the key pins are pointing sideways at an angle. Also at this point, the lightweight pin is blocked by a piece of the housing extending into the area between the lips (except as I said, there are no lips directly around the lightweight pin.)

(side view)
###########
###########
###########
######* #*##
######* #*##
**************
[keyway]*******
**************

Also at this very same point there is a small compartment in the housing which holds a heavy steel or lead ball (or cylinder.) It is too big to fit between the lips, but once the lightweight pin has hit the housing it is in perfect position to fall down into the gap that is around the pin. This ball is heavy enough to push the lightweight pin to the sheer line.

O=ball

(straight-on view)
########
#O######
#LLL-I-LLL
*****@***
*****K***

########
###--####
LLL#O-LLL
****I***
****K***

The ball does not prevent motion of the plug, because the edges of the lip are beveled and raise it back up into its compartment in the housing.

Whew. Hard to explain, but the mechanism itself is quite simple.

Basically, if someone tries to use a plug spinner to bypass the secondary driver pins, the lightweight pin will catch on the housing and prevent any further motion of the plug. In the time it takes for the ball to fall down and push the lightweight pin to the sheer line, the secondary driver pins will push into the plug and the locking bar will activate. I'd recommend that the secondary drivers be pointed in order to minimize the possibility of them being caught on the sheer line.

The only ways I can think to counteract this is to devise a tool (and I'm sure someone would) that would allow you to put pressure on all of the key pins so that the secondary drivers do not fall and lower them one by one until they set, or fill the lock with some sort of plaster or semi-squishy substance (but it can't be TOO squishy, especially if the secondary drivers have strong springs) to keep the key pins flush with the sheer line.

Or, of course, you can always impression.

I'm sure that there are more effective ways of making the pin tumbler more secure, but keep in mind:

1. This method uses ordinary house keys, and the lock functions like an ordinary lock except for a slight click and pause halfway through turning it.

2. Because tolerances don't *need* to be awesome and the extra parts are about as intricate than a regular pin tumbler, this shouldn't be horribly expensive--say 2x the cost of a cheap kwikset, worst case scenario 3x. That's still under $40 USD.

3. You can combine it with most other methods of security (security pins, thin keyways, sidebars, etc.)

Anyway, sorry for the rant. I probably don't have the faintest clue what I'm talking about, but I'd rather come up with a completely original piece of BS than whine about how I haven't even gotten the hang of our kwikset yet.

[ThE_MasteR]

I don't understand anything.

Maybe a drawing in paint shop ?

[LodeRunner]

I don't understand anything.

Not even the basic concept of two rows of driver pins? The rest of it is just me explaining a way to negate a plug-spinner attack (which would allow the plug, once you've picked the first line of pins, to skip over the second line of driver pins.) The first line of pins is pickable as normal. You then turn the plug and run into a second line of pins before it unlocks. This second line of driver pins (you keep the same keyed pins in the plug) is designed to freeze up if it "detects" that you aren't using a key (i.e. if the driver pins drop too far.) This makes picking extremely hard, if not impossible. That's the main point of my idea; maybe someone else can explain my anti-plug spinner thing better.

Right now, I need to sleep.

[Chrispy]

Your ideas remind me of sidebars, BiLocks, V7s and Lockwood Twins. However, it's good that you're thinking of new ideas. Maybe I just didn't read enough into your post.

[ThE_MasteR]

I am more of a visual person, so when there's to much writting, I become nuts !

[n2oah]

Sorry, but your idea has already been put into production. Creative thinking, though. The lock that uses this principle is the M&C Antiklop.

[LodeRunner]

Sorry, but your idea has already been put into production. Creative thinking, though. The lock that uses this principle is the M&C Antiklop.

Which parts?

All of it?

Whoa.

Re: Chrispy

I'm not entirely clear on how sidebars work. I think it has something to do with angled keys and rotating the pins. Haven't heard of any ot the others... like I said, I'm still trying to get the hang of this dang Kwickset .

Oh well, the pin tumbler has been around forever, I guess the only real options were that it was already done or it wouldn't work. Was fun to brainstorm, though.

[LodeRunner]

"M&C Antiklop has trap pins that block plug if the key does not
keep the bottom pins pushed all the way, cannot be bypassed with
spinner."

I'll be , you're right! lol.

[Chrispy]

When a lock has a sidebar, there are two things stopping the plug from turning, the pins and the sidebar. Sidebars work on the principle that each pin will have a small hole on the side of it. When the pins are aligned to the correct height, the holes line up too, allowing the sidebar (a bar along the side of the chambers that has tiny prongs for each hole) to fall into these holes and allow the plug to turn.

[How]

Not all sidebar locks have angled or rotating pins. You're describing a Medeco, but general motors has used sidebar technology for a long time in their automobiles. The sidebar is the only item blocking the turn of the plug on the auto locks, though, where as the Medeco the pins themselves block, as well as the sidebar blocking.
Disk, wafer and pin tumbler locks use sidebar technology.