Re: Filing Cabinets That Use Electronic Access?

["Bill" <billnomailnospamx@xxxxxxxxx>]

"W"  wrote in message
> So let me ask does *any* third party make an office filing cabinet
> that has
> a solinoid activated locking bar that we could wire into?
>

There are electronic combination locking vertical filing cabinets.
Note these tend to be higher security cabinets. I just looked at the
prices...

$2,229.00 for cabinet.
$537.00 for add-on electronic combination lock
=======
$2766.00  Total, but shipping probably extra.

http://www.filingtoday.com/Fireproof_Fire-King_Vertical_Files_Cabinet_1-Hour_Rated.html

(For more search for filing cabinet combination lock.)

Note: The way these may work is that the top drawer only has this lock
on it. You enter the combination, then can open the top drawer. Then
you could open the lower drawers. So I think you need to open the top
drawer a bit in order to be able to open the lower drawers? You would
need to verify that.

Anyway that would have a drawback as to dependability so far as what
you want to do. A flexible cord would need to be wired to the top
drawer. Each time the drawer was opened it would stretch the cord.
That cord might last many years, but eventually it would fail and need
to be replaced.

And with such an electronic combination lock, you would pretty much
need to buy one, then take it apart to see if it could be modified so
just the lock portion could be wired to you card access system. Most
probably it could, however it might not be possible to modify it.
Pretty expensive way to find out if you could use a product or not!

If you already owned these cabinets, then that would be another
matter.

I think it would be much less expensive to have a custom locking
mechanism made for your existing filing cabinets.

I think this could be done by placing an electric solenoid / actuator
below the lowest drawer. Then the wiring to this would not need to
move as the actuator would be bolted to the cabinet and not a drawer.
Then no batteries needed as power for the actuator would come from the
wire / card access system.

I think the best way to approach this would be to get an electric
solenoid / actuator, THEN find a "mechanical type" who could design
rods / bars / levers, etc. which would connect the actuator to your
existing filing cabinet locking bar from below. That type of person
you would find at a machine shop. If you could take a filing cabinet
to this person, a soleonid / actuator, a battery to operate the
solenoid, and then tell the person how you connect the actuator wires
to the solenoid to get it to lock / unlock, then he could make and
install the interconnecting mechanism to do the rest.

It takes a LOT of pressure to move the locking bar on some filing
cabinets. That is... A lot of pressure from an electrical device. The
more force it can provide, the higher the cost of the actuator /
solenoid. With that said, a cheaper design might be to install a knob
where the existing key lock is. The solenoid / actuator would *allow*
the locking bar on the side of the cabinet to move freely. Then a
person would "do the work" of moving the bar by then turning the knob
to move the locking lever.

The mechanical type person could design this so it stayed unlocked
once it was unlocked. Or so it re-locked each time the drawers were
closed.

Anyway it would be easy to find a "mechanical type" to do the
mechanical parts for you. Look for an older guy. If all else fails, go
to your local university and find a mechanical engineering student.
They are all broke and will work cheap. Then need the money! And just
a few hundred dollars will make them happy or pay by the hour.

Also "mechanical types" and "electrical types" are different breeds!
Mechanical people do not understand electrical stuff and electrical
people are not so good at mechanical stuff. You need to get two
separate people for this.

Anyway the only question remaining is how does the "output" of a card
access system work? What is the output voltage? 12 volts DC? How much
amperage can it provide? 1 amp? How many different outputs can it
operate? (different doors it is designed to open? In your case, how
many filing cabinets do you have? Does the card access system have
that many different outputs?)

Then how does the card access system output work? (Like it was opening
a door.) Does it provide 12 volts for say 4 seconds, then power off?
Can this be changed to longer shorter in settings or is that time
fixed?

And note that you would NOT want the actuator to remain powered for
the full time the cabinet is open! Like powered for 8 hours. Solenoids
/ actuators get hot when powered on for a long time. They can burn
out. Best is briefly on for a few seconds each time something is
opened.

Then if the above is how a card access system works, next would come
the type of solenoid you would want. Some will spring forward when
power is applied, then return when power is removed. Others will
spring forward when power is applied, then stay then when power is
removed. Then you need to reverse power to move it the opposite
direction.

So you would need a solenoid / actuator which would work along with
the output of your card access system.

A device which could work is the electric door lock actuator on cars.
Some of these work by moving one direction when power is applied, then
it stays there. And it will move the opposite direction when power is
reversed. You can get these cheap from automotive wrecking yards if
you just want to play with one. They are located in the door of the
car and 12 volts DC (car battery) operates them of course.

Or search google.com for solenoid. Or for actuator.

People who play / work on robots are quite familiar with solenoids and
actuators. Again a university electrical engineering department would
provide a host of people who would know all about this.

Before you do anything, remove the bottom drawer from one of your
filing cabinets and see if there is room below the drawer for an
electrical actuator....