deadbolt lock - please help

[digital_blue]

I think there's merit to your idea Omi. I actually would envision a knobset that functions this way. When the interior handle is turned the deadbolt retracts and stays retracted until the door is closed, perhaps triggered by the door jam. Something like that.

Vector: Though I see where you're coming from, I don't agree that latches are inherently less secure. Perhaps from a bypass perspective, yes. But in a high traffic area a deadbolt is problematic because it requires that someone exiting lock the door behind them. This required user interaction represents its own security concerns. An inadvertently unlocked door is a greater risk than one that can be slipped.

db

[Chrispy]

When the interior handle is turned the deadbolt retracts and stays retracted until the door is closed, perhaps triggered by the door jam. Something like that.

Similar to a screen door lock, like a Whitco Tasman.

That would be easily achieved with some planning. The only problem I think would be wear on the parts, they would have to be replaced sooner than a standard lock.

[Omikron]

I think made with the proper materials, and proper design, it should last just as long as the lock, as long as it's properly maintained.

[alon]

Thanks for all your kind answers
It's been a great help
But, I still have a question:
Can you explain or send a visual diagram how a deadlatch works?
How does it avoid being retraced after locking by shuting the door???

[Omikron]

Thanks for all your kind answers
It's been a great help
But, I still have a question:
Can you explain or send a visual diagram how a deadlatch works?
How does it avoid being retraced after locking by shuting the door???

Deadbolt

The latch's operation is very simple. It's just a sloped piece of metal with a spring behind it. On most latches, there's nothing preventing you from pushing the latch back in if you can get to it.

[vector40]

Er.

That's true of a plain latch. But the meaning of a deadlatch is actually the little smaller, D-shaped piece of metal that rides alongside the latch. See, when you close the door, the latch itself will drop into the strikehole, blocking the door from moving. But that little deadlatch? That won't go in, at least not on a properly-fitted door -- but it won't be out of the jam, either. It'll be pushed against the strikeplace, completely depressed (or nearly so)... and when the deadlatch is depressed, the latch is "dead" -- you can't move it manually, though of course the knob still works.

Same sort of thing on other latch mechanisms that don't look quite the same... pretty much all better systems have some kind of deadlatch.

Anti-shimming safeguard.

[Omikron]

Er.

That's true of a plain latch. But the meaning of a deadlatch is actually the little smaller, D-shaped piece of metal that rides alongside the latch. See, when you close the door, the latch itself will drop into the strikehole, blocking the door from moving. But that little deadlatch? That won't go in, at least not on a properly-fitted door -- but it won't be out of the jam, either. It'll be pushed against the strikeplace, completely depressed (or nearly so)... and when the deadlatch is depressed, the latch is "dead" -- you can't move it manually, though of course the knob still works.

Same sort of thing on other latch mechanisms that don't look quite the same... pretty much all better systems have some kind of deadlatch.

Anti-shimming safeguard.

Yep, your explaination is much better. Thanks for clarifying, vector40.

[alon]

sorry but still need more clarification

when the latch is in the jumb, what with the dead latch
how it works inside???
they look as if they are attached, that why i ask again

[DaveAG]

You are absolutely right vector40, and that's why I'm so intrigued by the idea of an automatically engaging deadbolt. Perhaps when you unlock it, the bolt is held in under spring tension. When the door is shut, a little mechanical latch could hit some sort of strikeplate, releasing the spring tension and allowing the bolt to fully extend, perhaps even locking in place via some mechanism, only retracting when the cylinder is operated again.

http://www.safelocks.co.uk/acatalog/nightlatches.html

The Ingersoll SC71 has it so that the angled top part as it is pushed in, pushes out the deadbolt. The strike plate has a hole for the deadbolt but not for the angled piece at the top, so as the door is slammed shut, the deadbolt is automatically extended into the strike plate.

Operation of the cylinder will then withdraw the deadbolt regardless of the upper pieces position. Unless you double lock with the key from outside, so will the handle on the inside. My parents have a keyed alike set on the front door, the back door, and the door from the garage to the house. All backed up with some keyed alike BS3621 Chubb branded deadlocks. The front door only lets you into the porch which then has another 5 lever lock (possibly non-BS) and a standard yale nightlatch. Quite why they got such a system installed I will never know, but I pity any locksmith called to a lockout at their house.

[Omikron]

You are absolutely right vector40, and that's why I'm so intrigued by the idea of an automatically engaging deadbolt. Perhaps when you unlock it, the bolt is held in under spring tension. When the door is shut, a little mechanical latch could hit some sort of strikeplate, releasing the spring tension and allowing the bolt to fully extend, perhaps even locking in place via some mechanism, only retracting when the cylinder is operated again.

http://www.safelocks.co.uk/acatalog/nightlatches.html

The Ingersoll SC71 has it so that the angled top part as it is pushed in, pushes out the deadbolt. The strike plate has a hole for the deadbolt but not for the angled piece at the top, so as the door is slammed shut, the deadbolt is automatically extended into the strike plate.

Operation of the cylinder will then withdraw the deadbolt regardless of the upper pieces position. Unless you double lock with the key from outside, so will the handle on the inside. My parents have a keyed alike set on the front door, the back door, and the door from the garage to the house. All backed up with some keyed alike BS3621 Chubb branded deadlocks. The front door only lets you into the porch which then has another 5 lever lock (possibly non-BS) and a standard yale nightlatch. Quite why they got such a system installed I will never know, but I pity any locksmith called to a lockout at their house.

Yes!!!

That is EXACTLY what I was trying to describe!

Thanks!

[vector40]

sorry but still need more clarification

when the latch is in the jumb, what with the dead latch
how it works inside???
they look as if they are attached, that why i ask again

They do look like they're attached, but check out your front door; they move individually.

I haven't a clue how the mechanism works inside, to be honest.

[Wade]

what is the purpose of the half-cylinder looking thing in front of the latch?

[digital_blue]

what is the purpose of the half-cylinder looking thing in front of the latch?

That's what makes it deadlatch. When the door closes, the actual latch goes through the hole in the strike plate, but that little "finger" stays depressed. In this position, the latch can not be pushed back, thus preventing slipping the latch.

Hope that clears it up.

Cheers!

db

[vector40]

what is the purpose of the half-cylinder looking thing in front of the latch?

Thanks DB.

[Omikron]

what is the purpose of the half-cylinder looking thing in front of the latch?

That's what makes it deadlatch. When the door closes, the actual latch goes through the hole in the strike plate, but that little "finger" stays depressed. In this position, the latch can not be pushed back, thus preventing slipping the latch.

Hope that clears it up.

Cheers!

db

To be honest I never was fully aware of how it functioned as a deadlatch either. Thanks!