An
introduction to Barrow Town Hall Clock by Terry Ridal.
At approximately 130 years old the Barrow town hall clock could
be termed an old lady, she has had a few arthritic ailments which
have resulted in time standing still for Barrow occasionally.
The clock mechanism is of the Remintoir 30 second escarpment type,
a rare clockwork indeed, which moves the minute hand every 30
seconds. From time to time in its history changes have been made to
the mechanism which keeps the clock wound up. The main driving
force is still a weight on a cable as it always has been, but these
days the weight is wound up automatically by an electric motor. The
chimes and hour bells are driven electrically, the weights and
pulleys having been removed in the early 1960's. There is a
fascinating gearing system which keeps weight on the clockwork
whilst the cable is being wound which rejoices in the name of an
epicyclical weight transfer gear train system, which is a glowing
example of Victorian engineering prowess and ingenuity.
Sometimes the old girl has got too hot and seized up, her
thermostat can go on the blink. I know that sounds far
fetched but its true. In the clock cabinet there is a heater with a
thermostat control to keep her temperature fairly even. For,
although the clock looks very robust it is a very finely balanced
system and very little oil is used to keep it lubricated, too much
and if the temperature drops the oil thickens and stops the clock,
too little and if the temperature rises the oil dries out and drags
the works to a halt. We have fitted a new heater and thermostat to
try and keep the old girl comfy. All in all looking after her is a
bit like being a nursemaid with a quirky cranky old charge to keep
happy, but very interesting and rewarding when she's going ok.
"Watch" this space for updates from "Time to time".
Clock Maintenance
Maintenance October/ November 2005
First of all since the last bulletin, the clock has been
stripped and rebuilt, and had it's 10,000 mile service. Think of it
this way, a car gets serviced at say the first 2000 miles. The big
hand pointer tip travels about 57 miles per year, so it takes
about 35 years for the tip to travel 2000 miles. This means
that the big service recently is about the equivalent of a
10,000 mile service.
There have been a couple of hiccoughs since the service, one
was the memorable night when the Off trigger on the quarter
chime mechanism broke and the clock went through it's full
repertoire of chimes for four hours until I came in to stop it. The
next was when the iron bolts holding the cam ring onto the hour
drum succumbed to metal fatigue, and the whole ring fell off. The
repair carried out by my own fair hands with direction from the
engineer at Cumbria clock company meant tapping out the bolt holes
and fitting new bolts. Since then an electrical trigger has been
replaced on the quarter chime drive. Just this morning (4 November
2005) I have reported that the cushion spring on the rementoir
flyer has broken and needs replacing.
As most people will have noticed ,the bells are not chiming at
present. This is entirely due to the fact that they are currently
switched off, for the benefit of the poor souls fitting the anti
pigeon netting in the tower louvres, they were getting deafened
every quarter hour.
We have taken the opportunity of this period of quiet to have
the bell hangings checked, cleaned and painted. I anticipate that I
will be able to re-start them within a fortnight .
Previous Maintenance
As part of a maintenance program the driving weight pulley
system was inspected. The spindle pins were found to be badly word
and were allowing the pulley wheels to rub badly on their bridles.
This after only being in place since the clock was installed in
1885. Which was probably the last time any oil was applied as,
well, you can't get the staff you know.
Anyhow, after hanging the weight (about 4 cwt) on a rope from a
beam, removing and re-brushing the pulley wheels and inserting new
pins well greased. Then re-hanging the weight and loosing
about half a stone in sweat. Being underneath 4 cwt of iron
with nowhere to run is an interesting position to be in, the clock
was re-started.
Now with external friction eliminated as far as possible the
pulleys is sitting square and not dragging on their bridles, the
clock now relatively super efficient LOST time. About four minutes
per week.
This produced much head scratching as to how you regulate a
clock of this size, and mechanical type. The answer was that we
adjust the pendulum weight. There are two pegs on top of the
pendulum shaft to carry adjusting weights. Currently the clock is
kept in time by four 3/8 inch nuts and six washers!!
Question is do you add or remove weight to speed up the
mechanism ?
Answer: you add weight to the top of the pendulum to bring up
its centre of gravity effectively shortening the pendulum. So
allowing it to pass through the escarpment quicker and more
frequently. Therefore speeding up the clock. Obviously removing
weight has the reverse effect and slows it down.
At the end of September 2000 we had a short power cut.
Unfortunately is came at the worst possible time for the clock
mechanism. With no power to rewind the drive cable, the escarpment
just kept on ticking away, the weight now well past its automatic
rewind point, just kept on going until it reached the bottom of the
pit.
At this point the clock stopped and fractionally slackened the
cable enough to flip the trail end of the cable.
Out of its location point when the power to rewind came back
on. The trail end is held in place by a small wooden peg, which
under normal circumstances is quite sufficient. The cable has now
been re-attached with a new wooden peg, the re-wind has been
calibrated to avoid the problem arising again.
This cable problem does occur quite regularly. The last time
it happened was in 1929 when the Town Hall steward was a day late
re-winding the weights. The steward in question was not available
for comment.