US3945625A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Leaf spring
Assignee: Ressorts du Nord SA
•
Filing: 1973-05-21
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Granted: 1976-03-23
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Expires: 1993-05-21
Abstract
Abstract A very light and high efficiency leaf spring made from a curved hollow tube with flattened opposite ends, cross section of said tube having a form which varies progressively from the center part of the tube towards each opposite ends but wall of the tube having the same area in any cross section throughout the length of the leaf.
Inventors
- 👤 Michel Duchemin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 17:18
CPC Classifications
F; F16; F16F; F16F1/00; F16F1/02; F16F1/18; F16F1/185
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
158 words
A leaf spring comprising at least one curved tubular shaped leaf consisting in a hollow tube having a wall, an inner cavity, two opposite ends which are flattened in section and cross-section, said cross-section having a shape which varies substantially throughout the length of the leaf, the wall having a perimeter which is constant and a thickness which is substantially constant in each cross-section throughout the length of the leaf, wherein at least one portion of the tubular leaf adjacent one of said flattened ends is notched laterally on two opposite sides and defines two superimposed tab portions which are curved in opposite directions so as to constitute each one half of a fastening eye, and means are provided to connect together the ends of said two tab portions, a cylindrical tube inserted between the two curved tab portions at each end of the tubular leaf, said means being welding, and lateral reinforcing ribs on each tab portion.
Claim 2
Dependent Claim
158 words
A leaf spring comprising at least one curved tubular shaped leaf consisting in a hollow tube having a wall, an inner cavity, two opposite ends which are flattened in section and cross-section, said cross-section having a shape which varies substantially throughout the length of the leaf, the wall having a perimeter which is constant and a thickness which is substantially constant in each cross-section throughout the length of the leaf, wherein at least one portion of the tubular leaf adjacent one of said flattened ends is notched laterally on two opposite sides and defines two superimposed tab portions which are curved in opposite directions so as to constitute each one half of a fastening eye, and means are provided to connect together the ends of said two tab portions, a cylindrical tube inserted between the two curved tab portions at each end of the tubular leaf, said means being welding, and lateral reinforcing ribs on each tab portion.
Claim 3
Dependent Claim
23 words
A leaf spring as claimed in claim 1, wherein the tubular leaf has at least one narrower portion for holding fastening means stationary.
Claim 4
Dependent Claim
33 words
A leaf spring as claimed in claim 1, wherein the two portions of the tubular leaf respectively adjacent said two flattened ends have each a curved shape so as to constitute an eye.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-03-23 | 1979-09-22 | 1980-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-23 | 1983-09-22 | 1984-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-23 | 1987-09-22 | 1988-03-23 | $7700.00 | Window Closed / Lapsed |