Re: Filing Cabinets That Use Electronic Access?

["W" <persistentone@xxxxxxxxxxxxxx>]

"Bill" <billnomailnospamx@xxxxxxxxx> wrote in message
news:9eoqrdFdc3U1@xxxxxxxxxxxxxxxxxxxxx
> "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....

While this would be a fun project for someone, I really did not want to do
an R&D project.     R&D projects are both very expensive and also have a
very high chance of failure.   Further, without a lot of testing I would
expect reliability problems.    It's just not the path I wanted to go.

--
W