Replies

1. 
   DanH | May 12, 2006 10:05pm | #1

   The design is basically unchanged for maybe 70 years. They gotta be doing something right.

   If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
2. 
   ETG | May 12, 2006 10:23pm | #2

   They look very interesting.  I am very down on spring balances/spring pulley balances found on most windows today - both wood and vinyl.  They are not "balanced" with the sash weight so that most windows take some effort to "get started" when opening and later sometimes "take off" going to full opening.  Adjusting them is crude at best and really doesn't last long.

   Looks like these folks have their act together - they want your sash weight as well as dimensions - they are doing the right things.  My suggestion - try a set on a well used window for a couple of months - this is the time of year to open and close windows anyway.  You can then decide whether to go for the whole job based on your experience with the test window.

   Please give us an update - they look like they may be a good solution..

1. 
   Ragnar17 | May 13, 2006 12:52am | #4

   I am very down on spring balances/spring pulley balances found on most windows today - both wood and vinyl.  They are not "balanced" with the sash weight so that most windows take some effort to "get started" when opening and later sometimes "take off" going to full opening.  Adjusting them is crude at best and really doesn't last long.

   I am very much against most of the spring counterbalance systems in use today as well.  The biggest problem seems to be that (seemingly all) manufacturers use tension springs, and the resistance supplied by a tension spring varies proportionately to the distance it is deflected.  In other words, the amount of resistance *varies*; at some window positions, the counterbalance is undercompensating, at other positions it is overcompensating.  This inherent design flaw is "corrected" by introducing friction via jambliners.

   I've heard some people refer to these "clock springs" as "constant torque" springs.  If that is truly the case, they would supply a constant load that could match the weight of the window sash and perform similarly to a bonafide counterweight.  I'm going to ask the manufacturers if they have any engineering data to try to confirm this.

   One important benefit of this product that is immediately apparent is that you don't need to gain access to the counterweight chase for repair work.  Furthermore, since the counterweight chase is not necessary, it can be filled with insulation.

    

1. 
   DanH | May 13, 2006 02:04am | #5

   They're not literally constant force, but the spring inside is only stretched to maybe 30% of its potential range, producing a relatively linear force.
   If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison

2. 
   ETG | May 15, 2006 03:21am | #6

   I agree with your presmise.  It would be interesting to hear what the manufacturer has to say about the balances being a constant torque springs.  Please keep us posted.

3. 
   Stuart | May 12, 2006 11:40pm | #3

   I have those counterbalances in about ten windows on my sun porch.  As far as I know they were installed when the porch was built, in 1914. 

   One or two of them stick a little (they have some kinks in the metal tape that rolls up) but the rest of them still work fine.