Patent US4188878A successfully refreshed from Google Patents.
US4188878A
Expired / Lapsed
US
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Restraining device for use in drying lumber
Assignee: Weyerhaeuser Co
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Filing: 1978-11-03
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Granted: 1980-02-19
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Expires: 1998-11-03
Abstract
Abstract A restraining device is used in a dry kiln with a load of green lumber in order to reduce warpage during drying and cooling. A single restraint device is comprised of a pair of inverted leaf springs joined together at their centers and having a strap extending from one end of the top spring about the load of lumber and terminating at the other end of the top spring together with a tensioning device for the strap. Before the load of lumber is placed in the dry kiln, the tensioning device will draw down both the bottom and top leaf springs close to the load where the tensioning device will lock them in place. During drying, as the load shrinks, the top spring will be relaxed while the bottom spring will maintain a force across the width of the load, thereby substantially reducing warp.
Inventors
- 👤 Bruce L. Kuhnau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:26
CPC Classifications
B; B25; B25B; B25B11/00; Y; Y10; Y10T; Y10T24/00; Y10T24/14; Y10T24/1412; Y10T24/1416; Y10T24/44; Y10T24/44222; Y10T24/44641; Y10T24/44684
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
95 words
A restraining device for maintaining a substantially uniform compressive force over a load, comprising: a first pair of inverted leaf springs joined together approximately at their centers, with the bottom spring adapted to extend across a portion of the width of the load and with the top spring adapted to extend over a portion of the length of the bottom spring, and first means extending from one end of the top leaf spring about the load to the other end for drawing down the leaf springs whereby the compressive force over the load is established.
Claim 2
Dependent Claim
95 words
A restraining device for maintaining a substantially uniform compressive force over a load, comprising: a first pair of inverted leaf springs joined together approximately at their centers, with the bottom spring adapted to extend across a portion of the width of the load and with the top spring adapted to extend over a portion of the length of the bottom spring, and first means extending from one end of the top leaf spring about the load to the other end for drawing down the leaf springs whereby the compressive force over the load is established.
Claim 3
Dependent Claim
28 words
A restraining device as in claim 1 further including a locking device associated with the draw down means for maintaining the leaf springs in a drawn down condition.
Claim 4
Dependent Claim
24 words
A restraining device as in claim 1 in which the draw down means includes a flexible strap having a hook on one end thereof.
Claim 5
Dependent Claim
15 words
A restraining device as in claim 2 in which the locking device includes a rachet.
Claim 6
Dependent Claim
23 words
A restraining device as in claim 1 in which the bottom spring has a spring constant approximately twice that of the top spring.
Claim 7
Dependent Claim
24 words
A restraining device as in claim 1 in which the arch of the bottom spring is approximately one third that of the top spring.
Claim 8
Dependent Claim
38 words
A restraining device as in claim 1 further including a second pair of inverted leaf springs spaced from said first pair and having second draw down means associated therewith for establishing a second compressive force about the load.
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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) | 1983-02-18 | 1983-08-20 | 1984-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-02-18 | 1987-08-20 | 1988-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-02-18 | 1991-08-20 | 1992-02-19 | $7700.00 | Window Closed / Lapsed |