Window balance having four-loop cord configuration
A window balance has a channel with two ends. A top guide is disposed at one end of the channel and a bottom guide is disposed at the other end of the channel. One end of a spring is fixed within the channel. A movable block is secured to the other end of the spring. Rollers are rotatably mounted in the movable block. A single roller is rotatably mounted to a fixed block which is secured to the channel. A cord exit roller is disposed proximate the bottom guide. The first end of a cord is fixed relative to the channel. The middle portion of the cord is routed about the rollers mounted in the movable block and mounted to the fixed block. A second end of the cord is routed around the cord exit roller and is attachable to a window jamb.
1. A window balance comprising:
a channel having a first channel end and a second channel end;
a top guide disposed at the first channel end;
a bottom guide disposed at the second channel end;
a spring having a first spring end fixed within the channel and a second spring end;
a movable block secured to the second spring end;
a fixed block secured to the channel;
a plurality of rollers rotatably mounted in the movable block;
a single roller rotatably mounted in the fixed block;
a cord exit roller disposed proximate the bottom guide; and
a cord having a first cord end fixed relative to the channel, a middle cord portion routed about the plurality of rollers and the single roller, and a second cord end routed around the cord exit roller, wherein the second cord end is attachable to a window jamb.
2. The window balance of claim 1 , wherein the plurality of rollers are fixed relative to each other.
3. The window balance of claim 1 , wherein the first spring end is secured to the top guide.
4. The window balance of claim 1 , wherein the first spring end is secured to a rivet spanning the channel.
5. The window balance of claim 1 , wherein the cord exit roller is rotatably mounted to at least one of the fixed block and the bottom guide.
6. The window balance of claim 5 , wherein the fixed block and the bottom guide comprise a unitary part.
7. The window balance of claim 1 , wherein the cord exit roller is rotatably mounted to the channel.
8. The window balance system of claim 1 , wherein the first cord end is secured to at least one of the fixed block, the bottom guide, and a rivet spanning the channel.
9. A window balance comprising:
a channel having a first channel end and a second channel end;
a spring having a first spring end fixed relative to the channel and a second spring end;
a movable block secured to the second end of the spring;
a first roller having a plurality of roller surfaces, wherein the first roller is first rotatably mounted in the movable block;
a fixed block secured to the channel;
a second roller rotatably mounted to the fixed block;
a bottom guide secured to the second channel end;
a third roller rotatably mounted in the bottom guide; and
a cord having:
a first cord end secured to at least one of a rivet spanning the channel, the fixed block, and the bottom guide;
a middle cord portion routed about the first roller and the second roller; and
a second cord end routed around the third roller, wherein the second cord end is attachable to a window jamb.
10. The window balance of claim 9 , wherein the fixed block and the bottom guide comprise a unitary part.
11. The window balance of claim 9 , further comprising a top guide secured to the first channel end.
12. The window balance of claim 11 , wherein the first spring end is secured to the top guide.
13. The window balance of claim 9 , wherein the middle cord portion comprises a plurality of wraps around the first roller.
14. The window balance of claim 13 , wherein each of the plurality of wraps is disposed about a different one of the plurality of roller surfaces.
15. The window balance of claim 9 , wherein the second roller and the third roller are configured to rotate about substantially parallel axes.
16. The window balance of claim 9 , wherein the first roller, the second roller, and the third roller are configured to rotate about substantially parallel axes.
17. The window balance of claim 9 , wherein the second cord end terminates at a jamb mounting attachment.
18. The window balance of claim 9 , wherein the first cord end terminates at a hook.
19. The window balance of claim 9 , further comprising no more than three rollers.