US4357013A
Expired / Lapsed
US
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Reinforced foam core composite structure and method
Assignee: FN Herstal SA
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Filing: 1981-07-31
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Granted: 1982-11-02
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Expires: 2001-07-31
Abstract
Abstract A tubular frame structure adapted for use as a tennis racket having a rigid outer shell of composite material and an inner reinforced foam core including a foam portion and honeycomb reinforcement layers. The honeycomb reinforcement layers are oriented so that string holes passing through the frame pass through the foam core and rigid shell, but do not pass through the honeycomb layers. The use of honeycomb reinforcement layers is particularly well suited for use with elastic polymer foam cores.
Inventors
- 👤 David Fernandez
- 👤 Francis Van Dyck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:48
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/02; B29C44/12; B29C44/14; B29C44/16; A; A63; A63B; A63B49/00; A63B49/02; A63B49/10; A63B49/11; A63B60/00; A63B2049/103; A63B2209/00; A63B2209/02; A63B2209/023; A63B60/52; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24149
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
73 words
A tubular frame structure adapted for use as a tennis racket comprising: a reinforced foam core including a foam core and at least one honeycomb reinforcement layer; a rigid composite tubular shell surrounding said reinforced foam core; and a plurality of surfaces defining string holes passing laterally through said tubular frame structure, said string holes passing through said foam core and rigid composite tubular shell, but not passing through said honeycomb reinforcement layer.
Claim 2
Dependent Claim
73 words
A tubular frame structure adapted for use as a tennis racket comprising: a reinforced foam core including a foam core and at least one honeycomb reinforcement layer; a rigid composite tubular shell surrounding said reinforced foam core; and a plurality of surfaces defining string holes passing laterally through said tubular frame structure, said string holes passing through said foam core and rigid composite tubular shell, but not passing through said honeycomb reinforcement layer.
Claim 3
Dependent Claim
17 words
A tubular frame structure according to claim 1 wherein said foam core is an elastic polymer core.
Claim 4
Dependent Claim
22 words
A tubular frame structure according to claim 2 having two honeycomb reinforcement layers disposed between said elastic core and said rigid shell.
Claim 5
Dependent Claim
18 words
A tubular frame according to claim 3 wherein said honeycomb reinforcement layers are made from a lightweight metal.
Claim 6
Dependent Claim
37 words
A tubular frame according to claim 4 wherein said honeycomb reinforcement layer includes a plurality of honeycomb cells having axes perpendicular to the plane of said honeycomb layer, said honeycomb cells being sandwiched between honeycomb border layers.
Claim 7
Dependent Claim
26 words
A tubular frame structure according to claim 5 wherein said honeycomb cells are perpendiculr to said string holes passing through said rigid shell and elastic core.
Claim 8
Dependent Claim
18 words
A tubular frame structure according to claim 1 wherein said honeycomb reinforcement is made from a non-metallic material.
Claim 9
Dependent Claim
17 words
A tubular frame structure according to claim 2 wherein said elastic core is a flexible vinyl foam.
Claim 10
Dependent Claim
34 words
A tubular frame structure according to claim 8 wherein said rigid composite shell is made from resin impregnated fibers selected from the group consisting of graphite fibers, boron fibers, glass fibers and polyamide fibers.
Claim 11
Dependent Claim
88 words
In a tubular frame structure adapted for use as a tennis racket including a foam core surrounded by a rigid composite shell wherein the improvement comprises: at least one honeycomb reinforcement layer disposed between said foam core and said rigid composite shell; a plurality of surfaces defining string holes passing laterally through said frame structure, said string holes passing through said foam core and rigid composite shell, but not passing through said honeycomb layers whereby racket strings passing through said string holes are prevented from contacting said honeycomb.
Claim 12
Dependent Claim
88 words
In a tubular frame structure adapted for use as a tennis racket including a foam core surrounded by a rigid composite shell wherein the improvement comprises: at least one honeycomb reinforcement layer disposed between said foam core and said rigid composite shell; a plurality of surfaces defining string holes passing laterally through said frame structure, said string holes passing through said foam core and rigid composite shell, but not passing through said honeycomb layers whereby racket strings passing through said string holes are prevented from contacting said honeycomb.
Claim 13
Dependent Claim
17 words
An improved tubular frame structure according to claim 10 wherein said foam core is an elastic polymer.
Claim 14
Dependent Claim
19 words
An improved tubular frame structure according to claim 11 wherein said honeycomb layer is made from a lightweight metal.
Claim 15
Dependent Claim
18 words
An improved tubular frame structure according to claim 12 wherein said metal is aluminum or an aluminum alloy.
Claim 16
Dependent Claim
26 words
A reinforced foam core adapted for use in a tennis racket having a rigid tubular shell comprising a foam core sandwiched between parallel honeycomb reinforcing layers.
Claim 17
Dependent Claim
26 words
A reinforced foam core adapted for use in a tennis racket having a rigid tubular shell comprising a foam core sandwiched between parallel honeycomb reinforcing layers.
Claim 18
Dependent Claim
27 words
A reinforced foam core according to claim 14 wherein said foam core is an elastic foam and said honeycomb is made from lightweight aluminum or aluminum alloy.
Claim 19
Independent Claim
120 words
A method for producing a tubular frame structure adapted for use as a tennis racket comprising the steps of: preparing a heat foamable foam core precursor; sandwiching said foam core precursor between honeycomb reinforcement layers to form a reinforced foam core precursor; surrounding said reinforced foam precursor with uncured composite fibers; placing said fiber surrounded reinforced foam core precursor into a suitable tennis racket mold and heating said mold at sufficient temperature and for a sufficient time to form said tubular frame structure including a reinforced foam core and rigid composite tubular shell; and providing string mounting holes in said tubular frame structure which pass through said foam core and rigid shell, but do not pass through said honeycomb layers.
Claim 20
Independent Claim
120 words
A method for producing a tubular frame structure adapted for use as a tennis racket comprising the steps of: preparing a heat foamable foam core precursor; sandwiching said foam core precursor between honeycomb reinforcement layers to form a reinforced foam core precursor; surrounding said reinforced foam precursor with uncured composite fibers; placing said fiber surrounded reinforced foam core precursor into a suitable tennis racket mold and heating said mold at sufficient temperature and for a sufficient time to form said tubular frame structure including a reinforced foam core and rigid composite tubular shell; and providing string mounting holes in said tubular frame structure which pass through said foam core and rigid shell, but do not pass through said honeycomb layers.
Claim 21
Dependent Claim
22 words
A method according to claim 16 wherein said foam precursor includes a flexible vinyl polymer and a suitable amount of blowing agent.
Claim 22
Dependent Claim
28 words
A method according to claim 17 wherein said foam precursor is spirally wrapped flexible polyvinyl chloride having said blowing agent dispersed between the layers of said spiral wrapping.
Claim 23
Dependent Claim
12 words
A method according to claim 18 wherein said blowing agent is AZDN.
Claim 24
Dependent Claim
120 words
In a method for producing a composite tubular frame structure comprising a rigid outer shell and a core wherein a core precursor is surrounded by an uncured composite shell and placed in a mold whereupn heating of said mold, said core precursor expands to provide internal pressure necessary to shape said composite shell by forcing said shell against said mold, said shell curing to form said rigid outer shell and said expanded core precursor forming said core, wherein the improvement comprises: sandwiching said core precursor between two honeycomb layers, said layers being oriented so that string holes may be provided in said frame structure which pass through said outer shell and core, but do not pass through said honeycomb layers.
Claim 25
Dependent Claim
120 words
In a method for producing a composite tubular frame structure comprising a rigid outer shell and a core wherein a core precursor is surrounded by an uncured composite shell and placed in a mold whereupn heating of said mold, said core precursor expands to provide internal pressure necessary to shape said composite shell by forcing said shell against said mold, said shell curing to form said rigid outer shell and said expanded core precursor forming said core, wherein the improvement comprises: sandwiching said core precursor between two honeycomb layers, said layers being oriented so that string holes may be provided in said frame structure which pass through said outer shell and core, but do not pass through said honeycomb layers.
Claim 26
Dependent Claim
13 words
A method according to claim 20 wherein said core is an elastic polymer.
Claim 27
Dependent Claim
17 words
A method according to claim 20 wherein said honeycomb layers are made from aluminum or aluminum alloy.
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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) | 1985-11-01 | 1986-05-03 | 1986-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-01 | 1990-05-03 | 1990-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-01 | 1994-05-03 | 1994-11-02 | $7700.00 | Window Closed / Lapsed |