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In our previous article we spoke about nightlatches, aka ‘top locks’ or ‘Yale locks’. The fundamental thing about them is that you can just pull the lock shut and the door will lock automatically.

Still, there’s much more to it than that. There are a few different types out there that are worth knowing about:

The standard Yale lock

The standard Yale nightlatch has no special features to it. You pull it shut and it stays shut. It’s not a very secure lock and can normally easily be ‘credit-carded’ open.

Standard Yale lock

These ones are only really good for when you don’t need proper security, e.g. for your garden shed, where you just want to keep out the foxes.

(That said, if you double it up with a deadlock, you’ll be all right.)

The double-locking variety

Some Yale locks can be double-locked. Instead of just pulling the door shut behind you, you can turn the key to lock it. This effectively turns the Yale into a sort of deadlock.

There’s no way to credit-card a double-locked nightlatch, and also you can’t unlock it from the inside using the handle. This is an especially handy feature if you have a letterbox. Otherwise, someone might have put a tool through the letterbox to reach through to the handle.

The drawbacks of these ones are:

  1. They can be very confusing. If you want to get into your house and turn the key the wrong way, you accidentally lock yourself out. You try to turn the key the other way, and thereby undo the double-locking, but you still need to turn it again in order to actually open the door. A surprising amount of lock-outs happen this way.
  2. It’s not hugely fire-safe since there’s no way to unlock it from the inside if it has been double-locked.

Auto-deadlocking nightlatches

The double-locking nightlatch allows you to use your Yale lock as a deadlock. This is quite a handy feature, but needs improvement. That’s where auto-deadlocking nightlatches come in. This format removes both of the drawbacks mentioned above.

There are a few versions of auto-deadlocking locks:

  1. Roller-bolt nightlatch: a primitive form of auto-deadlocking nightlatch where, instead of the standard triangular bolt, you have a square bolt with a roller on it to make it possible to slam the door shut. This lock can’t be slipped open.
  2. Ingersoll nightlatch: this is quite similar, because the bolt, here, too, is square, like a deadlock.
  3. Trigger-bolt-operated nightlatch: these look like normal Yale locks with a triangular bolt, but they have a trigger-bolt just underneath or above the triangular bolt. This gets depressed when the door is shut, triggering the auto-deadlocking function.

These locks aren’t invulnerable, but they go quite a long way further than the regular Yale lock. I’m honestly surprised insurance companies don’t force you to have these, and let people get away with having regular Yale locks on their doors…

Chunky, high-security nightlatches

Then you get the chunky, high-security nightlatches.

Yale PBS1 auto-deadlocking nightlatch

The Yale PBS1 high-security auto-deadlocking nightlatch.

Above you can see a Yale PBS1, a lovely nightlatch. It’s robust, bulky and auto-deadlocking. It has a key-hole on the inside, with which you can ‘lock’ the handle. Once locked, you can’t pull it down to release the lock.

It also has a chunky cylinder-pull on the outside. That’s quite some protection!

The mortice nightlatch

The final type of nightlatch is the mortice nightlatch. A mortice is a term from carpentry, which means a recess cut into wood. A mortice nightlatch is therefore a nightlatch that is recessed into a door, as opposed to being fitted onto the surface of the door like other Yale locks.

These are often found on fancy new apartment blocks and communal entrance doors. They come in auto-deadlocking versions, too.

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