Patent US3763740A successfully refreshed from Google Patents.
US3763740A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Collapsible pistons
Assignee: National Aeronautics and Space Administration
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Filing: 1971-07-27
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Granted: 1973-10-09
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Expires: 1991-07-27
Abstract
Abstract A piston assembly for use in a hypervelocity gun comprising a forward cylindrical section longitudinally spaced from a rearward cylindrical section by an intermediate section. The intermediate section is longitudinally collapsible when subjected to a predetermined force, to allow the distance between the forward and rearward sections to be suddenly reduced.
Inventors
- 👤 J Fletcher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:36
CPC Classifications
F; F41; F41F; F41F1/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
198 words
A hypervelocity gun comprising: a combustion chamber; a pump tube connected at one end to said combustion chamber; a launch tube connected to said pump tube in axial alignment therewith and adapted to receive a projectile for mounting in the rearward end of said launch tube; and a piston assembly mounted in said pump tube and exposed at its forward end to pressurized low molecular weight gas and exposable at its rearward end to combustion gases emanating from said combustion chamber for forcing said piston assembly toward said projectile when mounted in said launch tube and further compressing said low molecular weight gas for propelling said projectile at hypervelocities, said piston assembly being adapted to collapse longitudinally after said low molecular weight gas has been compressed to a predetermined pressure so as to provide a pressure cycle at the base of said projectile which increases, decreases, and then increases again; said piston assembly comprising a forward cylindrical section, a rearward cylindrical section, and a frangible longitudinally collapsible intermediate section therebetween, said frangible portion being adapted to fail when the low molecular weight gas reaches said predetermined pressure whereby there is an inelastic, longitudinal collapse of said piston assembly.
Claim 2
Dependent Claim
198 words
A hypervelocity gun comprising: a combustion chamber; a pump tube connected at one end to said combustion chamber; a launch tube connected to said pump tube in axial alignment therewith and adapted to receive a projectile for mounting in the rearward end of said launch tube; and a piston assembly mounted in said pump tube and exposed at its forward end to pressurized low molecular weight gas and exposable at its rearward end to combustion gases emanating from said combustion chamber for forcing said piston assembly toward said projectile when mounted in said launch tube and further compressing said low molecular weight gas for propelling said projectile at hypervelocities, said piston assembly being adapted to collapse longitudinally after said low molecular weight gas has been compressed to a predetermined pressure so as to provide a pressure cycle at the base of said projectile which increases, decreases, and then increases again; said piston assembly comprising a forward cylindrical section, a rearward cylindrical section, and a frangible longitudinally collapsible intermediate section therebetween, said frangible portion being adapted to fail when the low molecular weight gas reaches said predetermined pressure whereby there is an inelastic, longitudinal collapse of said piston assembly.
Claim 3
Dependent Claim
96 words
A hypervelocity gun as set forth in claim 1 characterized in that said intermediate section comprises a first cylindrical body having a counterbore therein surrounded by an annular shoulder; a second member comprising a cylindrical portion of a diameter less than the diameter of said counterbore, and a frangible member between said first and second members separating said first and second members in longitudinally spaced relationship and being adapted to fail when the low molecular gas reaches said predetermined pressure thereby allowing said first and second members to assume a second and closer longitudinally spaced relationship.
Claim 4
Dependent Claim
34 words
A hypervelocity gun as set forth in claim 2, characterized in that said frangible member comprises an annular flange member at one end of said piston portion and in contact with said annular shoulder.
Claim 5
Dependent Claim
39 words
A hypervelocity gun as set forth in claim 2, characterized in that said frangible member comprises a disc member, one side of which contacts one end of said piston portion, the other side of which contacts said annular shoulder.
Claim 6
Dependent Claim
59 words
A hypervelocity gun as set forth in claim 1, characterized in that said intermediate section comprises a disc member having a plurality of radially spaced longitudinally extending voids therein, said disc member being longitudinally compressible when said molecular weight gas reaches said predetermined pressure by the failure and flow of the material of said disc member into said voids.
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) | 1976-10-08 | 1977-04-09 | 1977-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-08 | 1981-04-09 | 1981-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-08 | 1985-04-09 | 1985-10-09 | $7700.00 | Window Closed / Lapsed |