Patent US4165692A successfully refreshed from Google Patents.
US4165692A
Expired / Lapsed
US
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Frangible projectile for gunnery practice
Assignee: Calspan Corp
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Filing: 1977-10-25
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Granted: 1979-08-28
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Expires: 1997-10-25
Abstract
Abstract A sintered projectile having the same ballistic characteristics as a conventional combat projectile is provided with controlled strength properties and predetermined breakage lines. As a result, small, high drag fragments are produced on impact which minimizes ricochet hazards and provides a safer practice round.
Inventors
- 👤 Robert H. Dufort
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:30
CPC Classifications
F; F42; F42B; F42B8/00; F42B8/12; F42B8/14
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
50 words
A frangible projectile including: a brittle, sintered metal casing; a cavity formed in said casing; and an axially extendig sharp edged stress riser formed in said casing and forming at least a portion of the walls of said cavity whereby, upon impact, said casing will fracture along said stress riser.
Claim 2
Dependent Claim
50 words
A frangible projectile including: a brittle, sintered metal casing; a cavity formed in said casing; and an axially extendig sharp edged stress riser formed in said casing and forming at least a portion of the walls of said cavity whereby, upon impact, said casing will fracture along said stress riser.
Claim 3
Dependent Claim
83 words
A frangible practice projectile having similar ballistic characteristics to a corresponding combat round and including: a brittle, sintered metal casing having the dimensions, weight, center of gravity, spin inertia and transverse inertia of the corresponding combat round; an axially extending cavity formed in said casing; and an axially extending sharp edged stress riser formed in the interior of said casing and forming at least a portion of the walls of said cavity whereby, upon impact, said casing will fracture along said stress riser.
Claim 4
Dependent Claim
83 words
A frangible practice projectile having similar ballistic characteristics to a corresponding combat round and including: a brittle, sintered metal casing having the dimensions, weight, center of gravity, spin inertia and transverse inertia of the corresponding combat round; an axially extending cavity formed in said casing; and an axially extending sharp edged stress riser formed in the interior of said casing and forming at least a portion of the walls of said cavity whereby, upon impact, said casing will fracture along said stress riser.
Claim 5
Dependent Claim
64 words
A frangible projectile including: a brittle, sintered metal casing; a cavity formed in said casing; and sharp edged stress riser in the form of a tapering axial helix formed in said casing and forming at least a portion of the walls of said cavity whereby, upon impact, said casing will fracture along said stress riser and break into relatively small fragments having high drag.
Claim 6
Dependent Claim
64 words
A frangible projectile including: a brittle, sintered metal casing; a cavity formed in said casing; and sharp edged stress riser in the form of a tapering axial helix formed in said casing and forming at least a portion of the walls of said cavity whereby, upon impact, said casing will fracture along said stress riser and break into relatively small fragments having high drag.
Claim 7
Dependent Claim
95 words
A frangible practice projectile having similar ballistic characteristics to a corresponding combat round and including: a brittle, sintered metal casing having the dimensions, weight, center of gravity, spin inertia and transverse inertia of the corresponding combat round; an axially extending cavity formed in said casing; and sharp edged stress riser in the form of a tapering axial helix formed in the interior of said casing and forming at least a portion of the walls of said cavity whereby, upon impact, said casing will fracture along said stress riser into relatively small fragments having high drag.
Claim 8
Dependent Claim
95 words
A frangible practice projectile having similar ballistic characteristics to a corresponding combat round and including: a brittle, sintered metal casing having the dimensions, weight, center of gravity, spin inertia and transverse inertia of the corresponding combat round; an axially extending cavity formed in said casing; and sharp edged stress riser in the form of a tapering axial helix formed in the interior of said casing and forming at least a portion of the walls of said cavity whereby, upon impact, said casing will fracture along said stress riser into relatively small fragments having high drag.
References Cited (Backward Citations)
AT261448B
Cited
GB1442072A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-08-27 | 1983-02-26 | 1983-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-08-27 | 1987-02-26 | 1987-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-08-27 | 1991-02-26 | 1991-08-28 | $7700.00 | Window Closed / Lapsed |