Patent US4821431A successfully refreshed from Google Patents.
US4821431A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sandal with contained granular material to provide a pad for a person's foot
Assignee: Individual
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Filing: 1988-05-10
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Granted: 1989-04-18
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Expires: 2008-05-10
Abstract
Abstract Footwear consisting of a sandal having a plenum adapted to receive the person's foot as well as sand or other granular material, said sand providing a natural environment walking surface between the bottom of the person's foot and the sandal mid-sole, the footwear also having a bottom sole to engage the ground, the bottom sole a part of a lower surrounding cup-like shell with upraised heel part adapted to receive and secure the mid-sole, the upper rim portions of the lower shell providing means for securing a toe strap, heel strap, and instep strap, the instep strap and toe strap being loose and not contacting the foot while the person is standing but contracting the foot when the footwear is lifted up along with the foot. The footwear completely encloses the person's foot by continuing above the forward portion of the lower shell with an upper cover, and finally a plastic top closure material to engage the person's ankle. The described invention permits the free movement of the contained granular material allowing it to re-form and continually conform to the shape of the person's foot as the person utilizes the sandal in walking, and to thereby provide a healthful and comfortable article of footwear.
Inventors
- 👤 Donald W. Rieffel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:37
CPC Classifications
A; A43; A43B; A43B7/00; A43B7/14; A43B7/28
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
95 words
Footwear providing a natural environment walking surface for the bottom of a person's foot comprising: a lower shell adapted to receive the person's foot; a plurality of foot straps operably attached to said lower shell, said plurality of foot straps adapted to contain the person's foot; and granular material held within said lower shell interposed said lower shell and the bottom of the person's foot whereby the bottom of the person's foot contacts the granular material which provides the natural environment walking surface for the foot while the foot is contained within the lower shell.
Claim 2
Dependent Claim
95 words
Footwear providing a natural environment walking surface for the bottom of a person's foot comprising: a lower shell adapted to receive the person's foot; a plurality of foot straps operably attached to said lower shell, said plurality of foot straps adapted to contain the person's foot; and granular material held within said lower shell interposed said lower shell and the bottom of the person's foot whereby the bottom of the person's foot contacts the granular material which provides the natural environment walking surface for the foot while the foot is contained within the lower shell.
Claim 3
Dependent Claim
40 words
The footwear as defined in claim 1 wherein said lower shell defines an elongated cuplike structure having a front end and a heel end, and a flat bottom sole with perpendicularly extending sides, said sides partially enclosing the person's foot.
Claim 4
Dependent Claim
57 words
The footwear as defined in claim 2 wherein said lower shell perpendicularly extending sides rise at said heel end of the elongated lower shell to form a heel portion, said perpendicularly extending sides of said heel portion of a greater height than said lower shell perpendicularly extending sides at said front end of said elongated lower shell.
Claim 5
Dependent Claim
48 words
The footwear as defined in claim 3 further including a mid-sole situated interiorly to said lower shell, said mid-sole also elongated and having a front end and a heel end corresponding to said elongated lower shell front end and heel end, and said mid-sole receiving said granular material.
Claim 6
Dependent Claim
39 words
The footwear as defined in claim 4 further including an upper cover, said upper cover operably attached to said lower shell perpendicularly extending sides at said front end, said upper cover surrounding the forward portion of the person's foot.
Claim 7
Dependent Claim
36 words
The footwear as defined in claim 5 wherein said upper cover and said lower shell heel portion combine to form an opening adapted to receive the person's foot and pass the foot interiorly to the footwear.
Claim 8
Dependent Claim
52 words
The footwear as defined in claim 6 further including a top closure, said top closure operably connected to said lower shell heel portion and said upper cover proximate said opening, said top closure surrounding and engaging the person's foot above the instep to seal the granular material inside the sandal from escaping.
Claim 9
Dependent Claim
17 words
The footwear as defined in claim 5 wherein said mid-sole comprises an elongated block having a thickness.
Claim 10
Dependent Claim
26 words
The footwear as defined in claim 8 wherein said mid-sole comprises a wedge having a thickness greater at the front end than at the heel end.
Claim 11
Dependent Claim
26 words
The footwear as defined in claim 8 wherein said mid-sole comprises a wedge having a thickness greater at the heel end than at the front end.
Claim 12
Dependent Claim
50 words
The footwear as defined in claim 5 wherein said plurality of foot containing straps include a heel strap adapted to surround the person's heel, an instep strap adapted to encompass the instep of the person's foot, and a toe strap adapted to pass over the toes of the person's foot.
Claim 13
Dependent Claim
14 words
The footwear sandal as defined in claim 5 wherein said granular material comprises sand.
Claim 14
Dependent Claim
15 words
The footwear sandal as defined in claim 5 wherein said granular material comprises glass beads.
Claim 15
Dependent Claim
15 words
The footwear sandal as defined in claim 5 wherein said granular material includes a dessicant.
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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) | 1992-04-17 | 1992-10-17 | 1993-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-17 | 1996-10-17 | 1997-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-17 | 2000-10-17 | 2001-04-18 | $7700.00 | Window Closed / Lapsed |