Patent US4710984A successfully refreshed from Google Patents.
US4710984A
Expired / Lapsed
US
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Helmet for protection against impacts and a method of manufacturing the said helmet
Assignee: Motul SA
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Filing: 1985-06-14
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Granted: 1987-12-08
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Expires: 2005-06-14
Abstract
Abstract This helmet comprises an outer protective shell, an impact-absorbing layer made from a non-elastically compressible material, and a layer of elastically compressible material. A dome is interposed between the said layer and the impact-absorbing layer. The said dome is obtained by hot-drawing a 0.3 to 0.7 mm sheet material, of which the modulus of elasticity is between 1800 and 3500 N/mm 2 , the elongation at rupture less than 100% and the ultimate tensile strength between 30 and 100 N/mm 2 .
Inventors
- 👤 Jean-Jacques Asper
- 👤 Remi Cottenceau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:11
CPC Classifications
A; A42; A42B; A42B3/00; A42B3/04; A42B3/06; A42B3/062; A42B3/063; A42B3/10; A42B3/12; A42B3/125; A42C; A42C2/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
148 words
A helmet for protection against impacts, comprising a rigid outer protective shell, a first layer made from a non-elastically compressible material for absorbing the energy of the impact, an elastically compressible second layer forming the inner surface of the helmet, and an intermediate layer disposed between the two preceding layers for distributing the pressure exerted on both sides of a portion of the first layer for absorbing the energy of the impact over a large portion of the first layer, characterized in that the said intermediate layer is formed by a semi-rigid dome, which is independent of the outer protective shell and which is formed from a sheet material of 0.3 to 1 mm thickness, of which the modulus of elasticity is between 1800 and 3500 N/mm 2 , the elongation at rupture less than 100% and the ultimate tensile strength between 30 and 100 N/mm 2 .
Claim 2
Dependent Claim
148 words
A helmet for protection against impacts, comprising a rigid outer protective shell, a first layer made from a non-elastically compressible material for absorbing the energy of the impact, an elastically compressible second layer forming the inner surface of the helmet, and an intermediate layer disposed between the two preceding layers for distributing the pressure exerted on both sides of a portion of the first layer for absorbing the energy of the impact over a large portion of the first layer, characterized in that the said intermediate layer is formed by a semi-rigid dome, which is independent of the outer protective shell and which is formed from a sheet material of 0.3 to 1 mm thickness, of which the modulus of elasticity is between 1800 and 3500 N/mm 2 , the elongation at rupture less than 100% and the ultimate tensile strength between 30 and 100 N/mm 2 .
Claim 3
Dependent Claim
23 words
A helmet according to claim 1, characterized in that a central portion of the said semi-rigid shell is secured to the first layer.
Claim 4
Dependent Claim
18 words
A helmet according to claim 1, characterized in that the said semi-rigid shell is made from hard PVC.
Claim 5
Dependent Claim
21 words
A helmet according to claim 1, characterized in that the said dome is hot drawn from a sheet of thermoplastic material.
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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) | 1990-12-07 | 1991-06-08 | 1991-12-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-12-07 | 1995-06-08 | 1995-12-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-12-07 | 1999-06-08 | 1999-12-08 | $7700.00 | Window Closed / Lapsed |