Patent US3881771A successfully refreshed from Google Patents.
US3881771A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Convertible chair
Assignee: Individual
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Filing: 1973-04-27
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Granted: 1975-05-06
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Expires: 1993-04-27
Abstract
Abstract Convertible chair as converted to various configurations by means of parallelogram linkage actuated by a crank which is in turn actuated by screw means.
Inventors
- 👤 Daniel Amstutz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:37
CPC Classifications
A; A47; A47C; A47C1/00; A47C1/02; A47C1/031; A47C1/032; A47C1/03205; A47C1/03211; A47B; A47B85/00; A47B85/04; A47C1/034
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
302 words
Convertible chair comprising a seat, a back pivotally connected to the rear of said seat, and a leg rest pivotally connected to the front of said seat, double parallelogram linkage supporting said seat, back, and leg rest, said linkage comprising a first main bar supporting said seat and common to two parallelogrAms of said linkage, a second main bar pivotally connected near the center of said first main bar, and also common to both parallelograms of said linkage, a first shorter bar pivotally connected to one end of said first main bar and supporting said back, a second shorter bar pivotally connected to one end of said second main bar and one end of said first shorter bar to form a first parallelogram, a third shorter bar pivotally connected to the other end of said first main bar and supporting said leg rest, and a fourth shorter bar pivotally connected at one end to the other end of said second main bar and at the other end to said third shorter bar, a stationary platform, a movable platform mounted to slide vertically relative to said stationary platform, said seat being pivotally attached to said movable platform, motor driven screw means, and a crank connected to be driven by said screw means and to turn one of said main bars relative to the other between a first position in which said linkage supports said back and leg rest in a generally upright attitude and a second position in which said linkage supports said leg rest and back in a substantially horizontal attitude when said screw means is driven in a first direction, said crank being also connected to lift said linkage and seat vertically when said screw means continues to turn in said first direction after said crank has reached said second position.
Claim 2
Dependent Claim
302 words
Convertible chair comprising a seat, a back pivotally connected to the rear of said seat, and a leg rest pivotally connected to the front of said seat, double parallelogram linkage supporting said seat, back, and leg rest, said linkage comprising a first main bar supporting said seat and common to two parallelogrAms of said linkage, a second main bar pivotally connected near the center of said first main bar, and also common to both parallelograms of said linkage, a first shorter bar pivotally connected to one end of said first main bar and supporting said back, a second shorter bar pivotally connected to one end of said second main bar and one end of said first shorter bar to form a first parallelogram, a third shorter bar pivotally connected to the other end of said first main bar and supporting said leg rest, and a fourth shorter bar pivotally connected at one end to the other end of said second main bar and at the other end to said third shorter bar, a stationary platform, a movable platform mounted to slide vertically relative to said stationary platform, said seat being pivotally attached to said movable platform, motor driven screw means, and a crank connected to be driven by said screw means and to turn one of said main bars relative to the other between a first position in which said linkage supports said back and leg rest in a generally upright attitude and a second position in which said linkage supports said leg rest and back in a substantially horizontal attitude when said screw means is driven in a first direction, said crank being also connected to lift said linkage and seat vertically when said screw means continues to turn in said first direction after said crank has reached said second position.
Claim 3
Dependent Claim
41 words
Chair as claimed in claim 1 in which said screw means comprises a vertical screw which rotates in a nut pivotally connected to the end of said crank remote from the connection of said crank to one of said main bars.
Claim 4
Dependent Claim
36 words
Chair as claimed in claim 2 comprising two telescopic rods, one end of each rod being pivotally connected to said first main bar and the other end of each rod being pivotally connected to said nut.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-05 | 1978-11-04 | 1979-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-05 | 1982-11-04 | 1983-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-05 | 1986-11-04 | 1987-05-06 | $7700.00 | Window Closed / Lapsed |