Mounting system for a coil spring in a window counterbalance assembly
View Patent ↗A counterbalance system for counterbalancing the weight of a window sash in a window frame and the structure of the springs that provide the counterbalance force. Guide tracks are provided on a window frame to guide the movement of the window sash. Mounting slots are formed through the guide tracks at various points. Coil springs are provided to create the counterbalance force. Each coil spring is a coil of wound steel ribbon that has one end bent into an anchor configuration. The anchor configuration passes into, and is retained by, one of the mounting slots. This anchors one end of the coil spring to the guide track.
1. A counterbalance system for counterbalancing the weight of a window sash in a window frame, said system comprising:
a guide track coupled to said window frame, said guide track having a mounting slot formed therein;
a coil spring of steel ribbon wound into a coiled configuration, said coil spring having one end bent into an anchor configuration, wherein said anchor configuration includes a first ninety degree bend in said steel ribbon causes said steel ribbon to radially extend from said coiled configuration, and a second ninety degree bend in said steel ribbon, wherein said first ninety degree bend and said second ninety degree bend are bent in opposed directions and a lateral section of said steel ribbon extends between said first ninety degree bend and said second ninety degree bend, and wherein said anchor configuration passes into, and is retained by, said mounting slot, therein anchoring said one end of said coil spring to said mounting slot; and
a spring carriage coupled to said window sash and extending between said window sash and said guide track, wherein said spring carriage retains said coiled configuration of said coil spring between said window sash and said guide track so that said coil spring moves with said window sash in said guide track as said window sash is moved up and down causing said coil spring to wind and unwind.
2. The system according to claim 1 , wherein said mounting slot has a predetermined depth and said lateral section has a length at least as long as said predetermined depth.
3. The system according to claim 2 , wherein a locking lip extends between said second bend and said one end, wherein said locking lip has a length of at least one-quarter inch.
4. The system according to claim 3 , wherein said mounting slot is formed in a wall of said guide track, wherein said mounting slot extends through said wall from an exterior surface to an interior surface.
5. The system according to claim 4 , wherein said lateral section of said anchor configuration extends through said mounting slot when said anchor configuration of said coil spring is engaged with said mounting slot.
6. The system according to claim 5 , wherein said locking lip is biased against said interior surface of said wall when said coil spring is engaged with said mounting slot.
7. A coil spring for a window counterbalance system, said coil spring comprising:
a steel ribbon wound into a coiled section, wherein said steel ribbon terminates with an anchoring configuration external of said coiled section, said anchoring configuration including a first ninety degree bend, wherein said steel ribbon turns away from said coiled section into a lateral section that radially extends from said coiled section, and a second ninety degree bend that bends in a direction opposed to said first ninety degree bend, wherein said anchoring configuration turns away from said lateral section into a locking lip.
8. The coil spring according to claim 7 , wherein said locking lip extends between said second bend and a ribbon end, wherein said locking lip has a length of at least one-quarter inch.