Mysterious electronic door lock question

[IanB]

A new security door has been installed at work. It's the regular electronic variety--you swipe your badge and the door unlatches.

However, here's the interesting bit. The badge sensor is on the wall next to the door, but the solenoid that unlatches is inside the door, not in the door jamb. The door is a perfectly regular looking door with perfectly normal looking hinges and door latch. There are no visible wires going to or inside the door.

So, here's the mystery. How does the door mechanism operate? Wireless, presumably. But if wireless, how is it powered? And if by battery, how is the battery kept charged? I suppose there could be a long life lithium battery that has to be replaced periodically, but that seems high maintenance. It's puzzling... 

Does anyone with a knowledge of security systems have an idea how it might work? I expect I can ask around and find out soon enough, but I'm trying to figure out the design. It's not what I was expecting. I would have thought a door with dozens of people operating it all day would need some kind of permanent power source.

[rexxar]

Are there contacts on the jamb? Or maybe it's on the catch, are there spring contacts inside the jamb?

[IanB]

I looked all around the door. In fact, I saw the door before it was installed. It is a completely ordinary solid wooden door with a completely ordinary looking lockset installed in it.

[tsmith35]

Is it possible that this system from Securitron is being used? It's a strike plate that has a pair of internal plungers. One plunger holds the deadlatch (the little semi-circle pin that extends out next to the latch) in (toward the door) to prevent jimmying the latch. When the strike plate is directed to open the door, it retracts the deadlatch plunger, thereby allowing the deadlatch to pop out and the latch to be pressed in. At that point, the latch plunger is extended (along with the deadlatch plunger), pushing both the latch and deadlatch back into the door. Once you push the door open (or after a timed period), both plungers retract.

Another possibility is the .

[smashedProton]

My school has an equally puzzling system that works kinda similarly.  The detector is on one door, but it unlocks all of the doors to the gym  (about 20 doors).  They all buzz open at once.  But all of the door jambs are normal.  It looks like every door is battery operated 

[IanB]

The strike plate is completely standard with no special features, however that PowerJump device looks like a possibility. I didn't see anything like that today, but I will look more closely next time. If something like PowerJump is being used then it must have a battery backup because the door has been left open before being brought into use and the electronic latch works just fine with the door wide open.

[peter.mitchell]

Generally, when electric mortice locks are installed, there will be a cable transfer that looks like a spring cut into either the door near the hinge or the door frame.

However, there are a number of short range wireless systems, where they put a battery operated wireless door furniture on top of a standard mortice lock, and above the door in the ceiling they have a little wireless transmitter, and a cable going down the wall into the reader. It is a lot of really hard work routing a channel either around the door for the cable to go in (if the door isn't a plain door, eg, has glass) or it is very hard to drill a long straight hole all the way through a door. There is also another advantage, that you get live updates from the lock, the alternative is using a data-on-card system and using offline locks, which means you don't need to bring any cables to the door or lock, however, you don't get any door feedback, and if you do, it's very slow, eg, when the used card passes back past an active reader.

[tsmith35]

If something like PowerJump is being used then it must have a battery backup because the door has been left open before being brought into use and the electronic latch works just fine with the door wide open.

Perhaps something like this?

Take a look at the brands & model numbers on the latch and hinges. Perhaps that would provide more insight.

[IanB]

Perhaps something like this?

Take a look at the brands & model numbers on the latch and hinges. Perhaps that would provide more insight.

Ah, now the "Concealed Circuit Electric Hinge" looks like a very definite possibility. Especially since one of the hinges was left off the door and was only fitted when the rest of the door hardware was fitted. I think you may have nailed it!

[David_AVD]

I've seen (online) door locks that use a small internal battery and charge inductively when the door is closed.