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Balances
A:
These are what make your sash windows work... just as the weights did in the original windows.
Originally, on timber windows, the weight of the glass and sash was counterbalanced by a lead weight on the end of the cord. This meant that wooden windows would be easy to open (when not painted shut) and remain in the position required because the sash was the equal to the lead weights and so counter balanced.
Little or no effort was necessary to move the sash because there is no friction between the sash and the frame, that’s why they were often drafty and rattled.
Today, manufacturers have 5 basic types of balances to open the windows. Each is designed for a purpose and requires differing amounts of effort to raise or lower the sash...
- Clock springs or constant force balances
- Block and tackle or cord and pulley
- Wind up (Alumatilt)
- Pretensioned Spirals (Ultralift)
- Double springs and spirals (TORSO)
Whilst some manufacturers import goods from the USA direct, we source all our balances from a company that specialises in making balances, indeed they make each of the 5 types of balance listed and this is a summary of their experiences...
Should you need detailed information, check them out at www.caldwell.co.uk
Clock springs are exactly that. A little like a metal tape measure on its side, which unfolds when the windows are operated. Coupled with larger weights when required, they are used extensively in America for secondary or ultra lightweight windows. Tested to AMA (American Manufactures Association) they are not expected to exceed more than 3,000 opening cycles. Very competitive, but Caldwell refuse to import them into the UK as they are simply not sturdy enough for the UK market.
Block and Tackle. Again, extensively used in the USA on small lightweight windows. A nylon cord approx 2mm in diameter, wrapped around a pulley system and encased in a three sided channel, these balances are not expected to exceed 3,000 cycles and, again, not imported to the UK by Caldwell.
Wind-ups or Alumatilt. This is a lightweight continuous tube, encasing a twisted metal rod. These balances are sturdy, and competitive. However, because they need to be "wound up" they retain a twisted force throughout their, 5,000 cycles. This can lead to frequent adjustments normally demonstrated when a sash is opened and it drops a couple of inches by itself! A 2 year warranty is average for a product that is highly likely to require some adjustment through its life.
Pre-tensioned Spirals or Ultralift. A smooth operating balance with the tension "factory set" or pre-tensioned. These sturdy balances, are designed for weights up to 28kgs. We have had these independently tested at the BBA to exceed 20,000 cycles (that’s over 25 years if opened twice a day). A 5 year warranty for this reliable, factory set balance is entirely justified.
Double springs and spirals or TORSO. The Rolls Royce of balances!
Designed by a Dutchman in 1946, they epitomise great engineering. Individually manufactured in 0.5kg increments (1lb), and tailored for perfect lengths, these balances have two springs; one wound clockwise, the other anti clockwise. So as a sash is opened, one spring is getting longer and the other compressing, getting shorter... counterbalancing each other for their entire life.
This means they are immensely reliable.
When being tested for a Post Office Counters project they exceeded 50,000 cycles or simulated 68 years life expectancy if opened twice a day (actually they switched off the machine after 180,000 cycles!). The Torso balance is the premier of all balances, perfect for any size of window, and as such is covered by a 10 year warranty.
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