Assembly of the device.
Start with the old point motor and carefully dismantle it so that you
end up with one of the coils and the short lengths of fine copper wire
having been unsoldered from the paxolin / metal terminals.
Cut a square-ish bit of copper strip board and drill one 1/4 inch hole
in the centre and four 1/8th inch holes at the corners.
Glue the motor coil to the plain side of the copper stripboard so that
the centre is over the 1/4 inch hole. You will find that the plastic
case of the coil is a loose fit and I found it best to insert glue into
this too.
Push the two copper wire tails through holes in the stripboard and
solder each one to a separate track of copper strip.
Solder a pair of wires to the copper strips that you earlier soldered
the coil wires to. These will be the feed wires to the unit when it is
all fitted in place.
(If you have had to make do with plain paxolin here, then solder some
longer thin insulated wires on to the tails and secure to the coil with
tape so that they dont get pulled off)
Cut about an inch and a half piece from the Lollipop stick and file or
sand the ends round. (One end will already be round)
Drill and countersink a hole in the centre of the stick so that the 6BA
screw is a threaded fit and goes down level with the top surface.
Offer the stick up to between the track rails where it is going to be
used and with the hole for the 6BA bolt between two sleepers. mark the
stick for two more holes to take the panel pins so that they will be
between sleepers.
Drill fine holes in the stick for the panel pins.
Now drill the centre hole in the track bed that the lifting sleeving
will pass through ( 1/4 inch) and drill the two smaller holes in the
track bed that will act as guides along with the panel pins (1/8 inch)
Insert the panel pins to be flush with the top surface of the stick.
Find a drill bit or other rod that is a good fit for the tube in the
centre of the coil and use this as a locator by offering the coil up
from under the layout so that the drill bit or rod comes up through the
centre of the larger hole drilled in the track.
Using four small woodscrews secure the coil in this position under the
board.
Now take your piece of wire sleeving and thread one end of this onto
the 6BA bolt until it comes up to the underneath of the lollipop stick
and holds the bolt in tight.
Fit the assembly of the stick, pins, bolt and sleaving in position so
that it is flush with the track bed and you have some of the sleeving
sicking out of the bottom of the coil. Initially trim this sleeving to
be flush with the bottom.
(You may need to clip the panel pins shorter here depending on the
thickness of your baseboard.)
Put the lead washer you have made on the self tapping screw and thread
this screw into the sleaving by a couple of turns.
From underneath push up so that the stick lifts to the full height. You
will find this is far more than you will need to uncouple stock and you
will now need to keep trimming more off the sleeving until you get the
lift to the correct height.
If you over do this trimming then cut some more sleeving and begin
again.
Once you are satisfied that you have got the amount of lift correct
then wire the unit to a 12v DC supply via a push button and that's it.
Note (18th
November 2007)
Since the original design of the uncoupler I have experimented with
thin walled brass tubing instead of the cable sleeve as the lifting rod.
This has given an improved action to the uncoupler by reducing the
tendency for the lifting tube to bend slightly if you are not over it in
the centre when trying to uncouple.
The tubing I used was a free sliding fit inside the point motor and is
available from suppliers at most exhibition venues. I can't recall the
exact size of the piece I had but if you take the point motor coil along
with you then you should be able to find a length that will fit
perfectly.
Operation
Push the button and the self tapping screw is drawn into the coil thus
lifting the stick and the coupling hooks of your stock that are parked
over it. Simply drive the train away while holding the button down and
the stock will part.
Do not keep the button held any longer than you need to as the coil
will get warm and could be damaged if power is supplied to it for a long
time.
Several uncouplers of this design are in use on the Heywood Model
Railway Group "Rochwood" layout and have proved to be very
successful. |
