Hello all.

I've had very little energy for the past few weeks; but today I felt better
and got "stuck in" that window job.
Findings: the weights are the correct ones, and are attached to the sash
cords.
I'm able to raise the window to its full extent.
But (a big but?), with the window raised to its full extent, the bottom of
each weight is 8 inches approx. from the bottom of the weights' housing.
Now, I know a _little_about the law of levers (leverage/s?), and a possible
solution comes to mind. Does the distance between the pulley centre and the
weight attachment affect the force pulling on the window? And if so; if I
increase the length of the sash cord (or re-position it if it's wrongly
attached) so that the weight is just clear off the bottom (which I intend to
do anyway) will that make a difference?
As a matter of interest; the sash cord is not visible with the hatch open,
so I'm unable to add some weight as has been suggested by Ken.
P.S. I always mark the place where the sash cord is attached to the window,
but I think that in this case that will be a waste of time.

Thanks in advance for your comments.

Sylvain.

On Thu, 31 Aug 2006 17:36:23 GMT, "Sylvain VAN DER WALDE"
wrote:

Hello all.

I've had very little energy for the past few weeks; but today I felt better
and got "stuck in" that window job.
Findings: the weights are the correct ones, and are attached to the sash
cords.
I'm able to raise the window to its full extent.
But (a big but?), with the window raised to its full extent, the bottom of
each weight is 8 inches approx. from the bottom of the weights' housing.
Now, I know a _little_about the law of levers (leverage/s?), and a possible
solution comes to mind. Does the distance between the pulley centre and the
weight attachment affect the force pulling on the window? And if so; if I
increase the length of the sash cord (or re-position it if it's wrongly
attached) so that the weight is just clear off the bottom (which I intend to
do anyway) will that make a difference?
As a matter of interest; the sash cord is not visible with the hatch open,
so I'm unable to add some weight as has been suggested by Ken.
P.S. I always mark the place where the sash cord is attached to the window,
but I think that in this case that will be a waste of time.

Thanks in advance for your comments.

Sylvain.




I cannot comment on the "physics" aspect of what you say but when I was Googling
for an answer I did see that what you should do is raise the window to about 4
inches off the sill( cill),having moved the window inward to get access to the
rope and then hoist the weight right up to the top of it's box ( until you hear
it clunk ) then fix the sash cord to the window at the same place as the old
rope and trim any excess rope .

"Sylvain VAN DER WALDE" wrote in message
...
Hello all.

I've had very little energy for the past few weeks; but today I felt
better
and got "stuck in" that window job.
Findings: the weights are the correct ones, and are attached to the
sash
cords.
I'm able to raise the window to its full extent.
But (a big but?), with the window raised to its full extent, the
bottom of
each weight is 8 inches approx. from the bottom of the weights'
housing.
Now, I know a _little_about the law of levers (leverage/s?), and a
possible
solution comes to mind. Does the distance between the pulley centre
and the
weight attachment affect the force pulling on the window?

Aye, it is a little, too: leverage (torque, moment, call it what you
will) is the product of the force and the perpendicular distance of its
line of action from the "pivot point". In this case, the moment is the
weight * radius of the pulley, since the line of action is tangential to
the pulley.

So changing the length of the cord will make no difference.

How do you know the weights are correct? One could even argue that,
since they don't hold the window up, by definition they are wrong. Are
you sure the glass has never been changed?


--
Kevin Poole
**Use current month and year to reply (e.g. )***

"Sylvain VAN DER WALDE" wrote in message
...
Hello all.

I've had very little energy for the past few weeks; but today I felt
better
and got "stuck in" that window job.
Findings: the weights are the correct ones, and are attached to the sash
cords.
I'm able to raise the window to its full extent.
But (a big but?), with the window raised to its full extent, the bottom of
each weight is 8 inches approx. from the bottom of the weights' housing.
Now, I know a _little_about the law of levers (leverage/s?), and a
possible
solution comes to mind. Does the distance between the pulley centre and
the
weight attachment affect the force pulling on the window? And if so; if I
increase the length of the sash cord (or re-position it if it's wrongly
attached) so that the weight is just clear off the bottom (which I intend
to
do anyway) will that make a difference?
As a matter of interest; the sash cord is not visible with the hatch open,
so I'm unable to add some weight as has been suggested by Ken.
P.S. I always mark the place where the sash cord is attached to the
window,
but I think that in this case that will be a waste of time.

Thanks in advance for your comments.

Sylvain.





The law of levers as you quote is not really valid here as the sash cord
should pass over only one pulley at the top of the window. If more pulleys
were used then you get into ratio and all that and it does make a
difference.

I would guess that the most likely answer is that the glass has been changed
at some time for thicker and therefore heavier glass, and this has now
"upset" the balance of the window.

the only real solution is to add some extra weight until the sash is
balanced.

Hth

DeeBee

On Thu, 31 Aug 2006 18:11:02 GMT, "DeeBee"
wrote:



The law of levers as you quote is not really valid here as the sash cord
should pass over only one pulley at the top of the window. If more pulleys
were used then you get into ratio and all that and it does make a
difference.

I would guess that the most likely answer is that the glass has been changed
at some time for thicker and therefore heavier glass, and this has now
"upset" the balance of the window.

Hey, I just wondered what abou the weight of layer upon layer upon
layer upon layer USW.USW.USW. of gloss paint? Both sides !

the only real solution is to add some extra weight until the sash is
balanced.


Or take it off the window.

DG

"Stuart" wrote in message
...
On Thu, 31 Aug 2006 17:36:23 GMT, "Sylvain VAN DER WALDE"
wrote:

Hello all.

I've had very little energy for the past few weeks; but today I felt
better
and got "stuck in" that window job.
Findings: the weights are the correct ones, and are attached to the sash
cords.
I'm able to raise the window to its full extent.
But (a big but?), with the window raised to its full extent, the bottom of
each weight is 8 inches approx. from the bottom of the weights' housing.
Now, I know a _little_about the law of levers (leverage/s?), and a
possible
solution comes to mind. Does the distance between the pulley centre and
the
weight attachment affect the force pulling on the window? And if so; if I
increase the length of the sash cord (or re-position it if it's wrongly
attached) so that the weight is just clear off the bottom (which I intend
to
do anyway) will that make a difference?
As a matter of interest; the sash cord is not visible with the hatch open,
so I'm unable to add some weight as has been suggested by Ken.
P.S. I always mark the place where the sash cord is attached to the
window,
but I think that in this case that will be a waste of time.

Thanks in advance for your comments.

Sylvain.


I cannot comment on the "physics" aspect of what you say but when I was
Googling
for an answer I did see that what you should do is raise the window to
about 4
inches off the sill( cill),having moved the window inward to get access to
the
rope and then hoist the weight right up to the top of it's box ( until
you hear
it clunk )

then fix the sash cord to the window at the same place as the old rope and
trim any excess rope .

Thanks for that info, however:
Your informant is assuming that the sash cord will have been attached in the
correct place. That may not have been the case.
We are led to assume that the sash cord was always attached in the same
place _from new_. This can't always be the case.
I live in a house which is over 100 years old.
Does what I say make good sense? Or not?

Sylvain.

"Autolycus" wrote in message
...

"Sylvain VAN DER WALDE" wrote in message
...
Hello all.

I've had very little energy for the past few weeks; but today I felt
better
and got "stuck in" that window job.
Findings: the weights are the correct ones, and are attached to the sash
cords.
I'm able to raise the window to its full extent.
But (a big but?), with the window raised to its full extent, the bottom
of
each weight is 8 inches approx. from the bottom of the weights' housing.
Now, I know a _little_about the law of levers (leverage/s?), and a
possible
solution comes to mind. Does the distance between the pulley centre and
the
weight attachment affect the force pulling on the window?

Aye, it is a little, too:

Well, I did admit it.

leverage (torque, moment, call it what you will) is the product of the
force and the perpendicular distance of its line of action from the "pivot
point".

You've lost me here.

In this case, the moment is the weight * radius of the pulley, since the
line of action is tangential to the pulley.

I think that I just about understand this: Fitting a slighter smaller or
larger pulley would vary the pulling force on the window. Of course, this is
not a practical thing to do.

So changing the length of the cord will make no difference.

Yes, I accept that now.

How do you know the weights are correct?

I've changed sash cords on several similar windows in the flat. The weights
look alright.

since they don't hold the window up, by definition they are wrong.


Other factors are involved; one you mention yourself below.

Are you sure the glass has never been changed?

This matter has already been discussed; and no, I can't be sure that the
glass has never been changed, as the house is over 100 years old and I've
only lived in this flat since 1971.

Thanks for your useful contribution.

Sylvain.

--
Kevin Poole
**Use current month and year to reply (e.g. )***

"DeeBee" wrote in message
.uk...

"Sylvain VAN DER WALDE" wrote in message
...
Hello all.

I've had very little energy for the past few weeks; but today I felt
better
and got "stuck in" that window job.
Findings: the weights are the correct ones, and are attached to the sash
cords.
I'm able to raise the window to its full extent.
But (a big but?), with the window raised to its full extent, the bottom
of
each weight is 8 inches approx. from the bottom of the weights' housing.
Now, I know a _little_about the law of levers (leverage/s?), and a
possible
solution comes to mind. Does the distance between the pulley centre and
the
weight attachment affect the force pulling on the window? And if so; if I
increase the length of the sash cord (or re-position it if it's wrongly
attached) so that the weight is just clear off the bottom (which I intend
to
do anyway) will that make a difference?
As a matter of interest; the sash cord is not visible with the hatch
open,
so I'm unable to add some weight as has been suggested by Ken.
P.S. I always mark the place where the sash cord is attached to the
window,
but I think that in this case that will be a waste of time.

Thanks in advance for your comments.

Sylvain.

The law of levers as you quote is not really valid here as the sash cord
should pass over only one pulley at the top of the window. If more pulleys
were used then you get into ratio and all that and it does make a
difference.

Yes, that's already been well expained by another poster.

I would guess that the most likely answer is that the glass has been
changed at some time for thicker and therefore heavier glass, and this has
now "upset" the balance of the window.

Agreed. Other posters have stated this.

the only real solution is to add some extra weight until the sash is
balanced.

I now agree that it is "the only real solution" as advised now by yourself,
and by several other helpful posters.
And this is exactly what I will be doing.

Sylvain.

Hth

DeeBee

"Derek ^" wrote in message
...
On Thu, 31 Aug 2006 18:11:02 GMT, "DeeBee"
wrote:



The law of levers as you quote is not really valid here as the sash cord
should pass over only one pulley at the top of the window. If more pulleys
were used then you get into ratio and all that and it does make a
difference.

I would guess that the most likely answer is that the glass has been
changed
at some time for thicker and therefore heavier glass, and this has now
"upset" the balance of the window.

Hey, I just wondered what abou the weight of layer upon layer upon
layer upon layer USW.USW.USW. of gloss paint? Both sides !

the only real solution is to add some extra weight until the sash is
balanced.


Or take it off the window.

Ha! Ha! You're right about the weight of the paint. It's the original window
in a 100+ years old house.
And no, I'm not touching the paintwork in any way.

Sylvain.

DG

"Sylvain VAN DER WALDE" wrote in message
...

"Autolycus" wrote in message
...

"Sylvain VAN DER WALDE" wrote in
message ...

snip

In this case, the moment is the weight * radius of the pulley, since
the line of action is tangential to the pulley.

I think that I just about understand this: Fitting a slighter smaller
or larger pulley would vary the pulling force on the window. Of
course, this is not a practical thing to do.

Nope.

The weight pulls down on one side of the pulley, the window on the
other, so the radius, and thus the "leverage" is the same for both.

So changing the length of the cord will make no difference.

Yes, I accept that now.

How do you know the weights are correct?

I've changed sash cords on several similar windows in the flat. The
weights look alright.

since they don't hold the window up, by definition they are wrong.


Other factors are involved; one you mention yourself below.

But looking alright isn't really much help: they're only right if the
window more or less balances.


--
Kevin Poole
**Use current month and year to reply (e.g. )***

Sylvain VAN DER WALDE wrote in message
...
Hello all.

I've had very little energy for the past few weeks; but today I felt
better
and got "stuck in" that window job.
Findings: the weights are the correct ones, and are attached to the sash
cords.
I'm able to raise the window to its full extent.
But (a big but?), with the window raised to its full extent, the bottom of
each weight is 8 inches approx. from the bottom of the weights' housing.
Now, I know a _little_about the law of levers (leverage/s?),

Look forget all the "physics" crap and think logically
This is a simple balance issue, if the window wont stays up
the weights are not heavy enough.



-

"Autolycus" wrote in message
...

"Sylvain VAN DER WALDE" wrote in message
...

"Autolycus" wrote in message
...

"Sylvain VAN DER WALDE" wrote in message
...

snip

In this case, the moment is the weight * radius of the pulley, since the
line of action is tangential to the pulley.

I think that I just about understand this: Fitting a slighter smaller or
larger pulley would vary the pulling force on the window. Of course, this
is not a practical thing to do.

Nope.

The weight pulls down on one side of the pulley, the window on the other,
so the radius, and thus the "leverage" is the same for both.

So changing the length of the cord will make no difference.

Yes, I accept that now.

How do you know the weights are correct?

I've changed sash cords on several similar windows in the flat. The
weights look alright.

since they don't hold the window up, by definition they are wrong.


Other factors are involved; one you mention yourself below.

But looking alright isn't really much help: they're only right if the
window more or less balances.

You haven't read some of the other posts: A heavier glass pane may have been
fitted; and the accumulation of numerous coats of paint over the years (100+
years actually) will have increased the weight of the window.
Some decorators are notoriously dishonest (or lazy), and will not remove the
old paint before applying the new one.

Sylvain.


--
Kevin Poole
**Use current month and year to reply (e.g. )***

"Mark" wrote in message
...

Sylvain VAN DER WALDE wrote in message
...
Hello all.

I've had very little energy for the past few weeks; but today I felt
better
and got "stuck in" that window job.
Findings: the weights are the correct ones, and are attached to the sash
cords.
I'm able to raise the window to its full extent.
But (a big but?), with the window raised to its full extent, the bottom
of
each weight is 8 inches approx. from the bottom of the weights' housing.
Now, I know a _little_about the law of levers (leverage/s?),

Look forget all the "physics" crap and think logically

This is a simple balance issue, if the window wont stays up
the weights are not heavy enough.

As I suggested to a previous poster, you haven't read all the relevant
messages.
It's _already_ been agreed that what you say is correct, and therefore I've
decided to act on that info.
Thanks for your post.

Sylvain.


-

Sylvain VAN DER WALDE wrote:

Look forget all the "physics" crap and think logically


This is a simple balance issue, if the window wont stays up
the weights are not heavy enough.


As I suggested to a previous poster, you haven't read all the relevant
messages.

Why do you suppose we have to trawl through old messages in order to
help you? Can't you post a proper summary? AFAICS there are several
things you haven't told us: is this a recent problem or has it been the
case ever since you moved in? Does the window drop right down, or will
it stay open part-way? Have you checked the friction of the pulleys? &c.

Douglas de Lacey

"Douglas de Lacey" wrote in message
...
Sylvain VAN DER WALDE wrote:

Look forget all the "physics" crap and think logically


This is a simple balance issue, if the window wont stays up
the weights are not heavy enough.


As I suggested to a previous poster, you haven't read all the relevant
messages.

Why do you suppose we have to trawl through old messages in order to help
you?

The messages aren't old. They're all recent. I'm a polite person, and like
to answer each post; hence the numbers.

Can't you post a proper summary?

I have. I've added "UPDATE" to the subject line; and in my last message have
stated that a solution had been found and that I would act on it.

AFAICS there are several things you haven't told us:

They weren't asked before by anyone.

is this a recent problem or has it been the case ever since you moved in?

It's an old problem.

Does the window drop right down, or will it stay open part-way?

It drops right down; but the problem is that it won't stay up a few inches,
at least as far as the security stops that I've fitted.

Have you checked the friction of the pulleys? &c.

Yes.

Sylvain.

Douglas de Lacey

It drops right down; but the problem is that it won't stay up a few inches,
at least as far as the security stops that I've fitted.

If the window drops right down then the window is heavier than the
combination of weights on the 2 cords.

You will either have to reduce the weight of the window or add weight
to the cord weights

If the window only dropped an inch or two this would almost certainly
have been due to the sash cord being nailed to high on the side of the
sash

Looks like your going to have to remove some beading, damage some
paintwork and add some weights to the sash cords.

Charlie

charlieB wrote:
It drops right down; but the problem is that it won't stay up a few inches,
at least as far as the security stops that I've fitted.

If the window drops right down then the window is heavier than the
combination of weights on the 2 cords.

You will either have to reduce the weight of the window or add weight
to the cord weights

If the window only dropped an inch or two this would almost certainly
have been due to the sash cord being nailed to high on the side of the
sash

Looks like your going to have to remove some beading, damage some
paintwork and add some weights to the sash cords.

Charlie


When the lower sash is fully down, the sash weights are up at the top,
just behind the pulley wheels. If, when you raise the sash, the cords
travel over the pulley normally and there is no slack in them, then it
does sound as though the weights aren't heavy enough.