deadbolt lock - please help

[alon]

can someone please explain what is the difference between a bolt and a latch, or the difference between a dead latch and a deadbolt???
thanks

[illusion]

a latch is spring loaded and can be bypassed easily without damage.

a deadbolt locks in position and won't budge untill you unlock it.

[Shrub]

A bolt is a solid rectangle which is part of a dead bolt.

A latch is an angled bolt that is part of a dead latch.

A deadbolt is where a bolt is slid across by the mechs in the lock via the key and can only be locked that way.

A dead latch is a latch that can be in the lock position but because of the angled face it can push past the latch keep and the door lock itself, the latch is sprung and can be locked from one side so that the keyed cylinder doesnt work it from the other side.

[vector40]

You slam shut latches. You have to fiddle with bolts.

[Omikron]

You slam shut latches. You have to fiddle with bolts.

What about a deadbolt that automatically engages when the door is slammed shut? Then you have the best of both worlds!

[vector40]

Um... what, like an electronic bolt?

[Omikron]

Um... what, like an electronic bolt?

It could be electronic, but there must be a mechanical way of engaging it too. Anyone know of any that already do this?

[DrStu]

I don't think it would be very practical for residential entry doors. Imagine you are going outside to pick up your paper and your door swings closed. You would allways have to carry a key.

[MrB]

I don't think it would be very practical for residential entry doors. Imagine you are going outside to pick up your paper and your door swings closed. You would allways have to carry a key.

Actually the vast majority of front doors in Britain are fitted with nightlatches that work exactly like this. It is extremely easy to get locked out if the wind slams the door shut behind you. Must give UK lockies lots of business!

[Omikron]

I don't think it would be very practical for residential entry doors. Imagine you are going outside to pick up your paper and your door swings closed. You would allways have to carry a key.

Perhaps not, but it would be very useful for an access door that leads into a secured area, like a server room or a restricted area of an institution.

I'd be interested in exploring this idea further. Has anyone seen any mechanical implimentations of this?

[digital_blue]

As far as mechanical means go, there are many ways to get this accomplished with standard hardware. Many commercial key in knob locks remain locked even though the interior knob is turned. This allows someone to leave an area and the door locks behind them automatically. The same is often accomplished with lever sets and panic bars. These are all for medium security applications (like a small office server room). Higher security installations often have electronic access card systems, be it proximity and/or swipe cards, which provide increased physical security as well as audit controls.

db

[Omikron]

As far as mechanical means go, there are many ways to get this accomplished with standard hardware. Many commercial key in knob locks remain locked even though the interior knob is turned. This allows someone to leave an area and the door locks behind them automatically. The same is often accomplished with lever sets and panic bars. These are all for medium security applications (like a small office server room). Higher security installations often have electronic access card systems, be it proximity and/or swipe cards, which provide increased physical security as well as audit controls.

db

Heh, most proximity systems available on the market, including HID, are *HORRIBLE* as far as security goes. With modified scanner and some other cheap hardware you can record, and rebroadcast such cards and easily compromise a system. Perhaps one day if/when I am granted access to the advanced forum I will post some of the research and experiments a friend and I performed on some HID hardware.

[digital_blue]

Yes, I've read a bit of material on defeating proximity cards. However, they are still commonly used in reasonably high security applications (including access doors to all non-public areas at both local spam in Winnipeg ). There are, however, continually newer systems being introduced that address many of the methods that precious exploits have... umm... exploited. One installation I can think of uses a combination of both swipe cards AND proximity cards coupled with software linked to the surveillance system which monitors for piggybacking on an authorized user. Slick system really.

db

[vector40]

You guys are deviating. Remember my definition. You can slam a latch; you have to retract a bolt.

Really that's the point, isn't it? That's the core difference, I'd say. The reason an ordinary latch isn't as secure, fundamentally, is because it has to be able to retract itself when it presses against the strike. Sure, there are a number of other differences, but they stem from this -- this is the fact that categorizes knobsets into "latches" (things that hold the door shut) and bolts into "security" (things that keep the door safe).

If a latch retracts when it hits the strike, that means that (aside from the obvious fact that it has an angle in it) it has to be depressible. That's not a secure feature if people can access the latch when it's closed, and it's hard to avoid that, even with plates and guards. So we do things like add deadlatches, complex little gizmos that try and turn the latch INTO a deadbolt once it's closed. But deadbolts have it from the beginning; you have to manually open and manually close it, and therefore the mechanism is operable only via that one means, and if you can secure that, you're okay.

Am I way off base here? Again, there's obviously a host of other differences, but I really do think that this is where it all starts. Otherwise we wouldn't have a knobset and a deadbolt, we'd have a knobset and... a second latch.

[Omikron]

You guys are deviating. Remember my definition. You can slam a latch; you have to retract a bolt.

Really that's the point, isn't it? That's the core difference, I'd say. The reason an ordinary latch isn't as secure, fundamentally, is because it has to be able to retract itself when it presses against the strike. Sure, there are a number of other differences, but they stem from this -- this is the fact that categorizes knobsets into "latches" (things that hold the door shut) and bolts into "security" (things that keep the door safe).

If a latch retracts when it hits the strike, that means that (aside from the obvious fact that it has an angle in it) it has to be depressible. That's not a secure feature if people can access the latch when it's closed, and it's hard to avoid that, even with plates and guards. So we do things like add deadlatches, complex little gizmos that try and turn the latch INTO a deadbolt once it's closed. But deadbolts have it from the beginning; you have to manually open and manually close it, and therefore the mechanism is operable only via that one means, and if you can secure that, you're okay.

Am I way off base here? Again, there's obviously a host of other differences, but I really do think that this is where it all starts. Otherwise we wouldn't have a knobset and a deadbolt, we'd have a knobset and... a second latch.

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.