Claims
- 1. A small diameter single cone coil spring for use in a box spring, said single cone coil spring comprising
- a single strand of round cross section wire formed into a top loop and at least three additional helically wound loops of decreasing diameter, the end of said top loop being wrapped around the next adjacent loop to form a knot in said coil,
- the improvement wherein said top loop of said spring has a diameter of less than 31/2 inches so that said spring has increased firmness relative to otherwise identical springs having top loops of substantially greater diameter, and so that said spring exhibits a substantially straight line deflection curve over a major portion of its possible range of deflection.
- 2. The coil spring of claim 1 wherein said top loop diameter is maintained to an accuracy of plus or minus 0.015 inch through an arcuate section of at least 300.degree..
- 3. The coil of claim 1 wherein said single strand of wire has a nominal diameter maintained to an accuracy of 0.0005 inch.
Parent Case Info
This is a division of application Ser. No. 784,439, filed Apr. 4, 1977, now U.S. Pat. No. 4,112,528, which is in turn a continuation-in-part of application Ser. No. 726,811, filed Sept. 27, 1976, now abandoned.
US Referenced Citations (5)
Divisions (1)
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Number |
Date |
Country |
Parent |
784439 |
Apr 1977 |
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Continuation in Parts (1)
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Number |
Date |
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Parent |
726811 |
Sep 1976 |
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