The coil spring-loaded mechanism was invented in the early 19th century and was first used in double-hung windows in the 20th century. This type of window is still common in many homes today. The coil spring allows the window to be opened and closed with ease, and also provides counterbalance weights that help keep the window in place.
Other related questions:
Q: What are old windows with weights called?
A: Old windows with weights are called sash windows.
Q: When did they start using window weights?
A: The use of window weights dates back to the early days of glassmaking.
Q: How would you replace double-hung window balance Springs?
A: 1. Remove the window sash from the window frame.
2. Locate the balance spring system on each side of the window.
3. Remove the old balance spring system from the window.
4. Install the new balance spring system into the window.
5. Replace the window sash into the window frame.