US3766629A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of foam air filter elements
Assignee: Briggs and Stratton Corp
•
Filing: 1971-11-17
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Granted: 1973-10-23
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Expires: 1991-11-17
Abstract
Abstract A sleeve-like primary air filter element is cut from a block of resilient foam material, such as polyurethane. In relaxed condition the sleeve has a narrow, elongated race track shape, with straight side stretches that are parallel and slightly spaced apart flatwise, and portions curved on small radius that connect the ends of the straight stretches. It is slipped axially around a cylindrical secondary filter medium of corrugated paper, its resilience permitting ready deformation to ring shape.
Inventors
- 👤 L Lechtenberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:44
CPC Classifications
B; B26; B26D; B26D3/00; B26D3/006; F; F02; F02M; F02M35/00; F02M35/02; F02M35/024; Y; Y10; Y10S; Y10S55/00; Y10S55/05; Y10S55/13; Y10T; Y10T29/00; Y10T29/49; Y10T29/49789; Y10T83/00; Y10T83/869; Y10T83/8821; Y10T83/8828; Y10T83/8831; Y10T83/8832
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
97 words
The method of making an air filter which comprises: cutting from a block of resilient plastic foam material a sleeve in the form of an endless band having a pair of substantially long straight stretches that are connected with one another at their ends by curved portions which have concentric interior and exterior surfaces of small radius and which tend to hold said flat stretches parallel and spaced apart flatwise but close together when the sleeve is in relaxed condition so that the sleeve can be cut from the block of material with very little waste thereof.
Claim 2
Independent Claim
97 words
The method of making an air filter which comprises: cutting from a block of resilient plastic foam material a sleeve in the form of an endless band having a pair of substantially long straight stretches that are connected with one another at their ends by curved portions which have concentric interior and exterior surfaces of small radius and which tend to hold said flat stretches parallel and spaced apart flatwise but close together when the sleeve is in relaxed condition so that the sleeve can be cut from the block of material with very little waste thereof.
Claim 3
Dependent Claim
29 words
The method of claim 1, further comprising: deforming the sleeve to a substantially annular shape; and slipping it axially around the periphery of a cylindrical filter of corrugated paper.
Claim 4
Independent Claim
115 words
The method of forming a plurality of annular filter sleeves from a substantially rectangular block of resilient plastic foam material, with very little waste of the material, which method comprises: die cutting the block to form each sleeve in the shape of an endless band having a pair of straight, flat stretches that are connected at their ends by small radius curved portions of the band, said curved portions having concentric interior and exterior surfaces and disposing said stretches spaced apart flatwise but close together and parallel to one another when the sleeve is in relaxed condition, but said sleeve, by reason of the resilience of its material, being readily deformable to a ring shape.
Claim 5
Independent Claim
115 words
The method of forming a plurality of annular filter sleeves from a substantially rectangular block of resilient plastic foam material, with very little waste of the material, which method comprises: die cutting the block to form each sleeve in the shape of an endless band having a pair of straight, flat stretches that are connected at their ends by small radius curved portions of the band, said curved portions having concentric interior and exterior surfaces and disposing said stretches spaced apart flatwise but close together and parallel to one another when the sleeve is in relaxed condition, but said sleeve, by reason of the resilience of its material, being readily deformable to a ring shape.
References Cited (Backward Citations)
US3180010A
Cited
US1685678A
Cited
US3059312A
Cited
US3212242A
Cited
US3290870A
Cited
FR1387618A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |