Patent US3881478A successfully refreshed from Google Patents.
US3881478A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hard hat air curtain
Assignee: Donaldson Co Inc
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Filing: 1974-06-13
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Granted: 1975-05-06
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Expires: 1994-06-13
Abstract
Abstract An improved industrial helmet for protecting the wearer against inhalation of air-borne particulate matter, the helmet having a bill provided, along its outer edge, with a member creating a high velocity air curtain enclosing the wearer''s face and attaching thereto only at the sides, and further provided, over a major portion of its lower surface, with diffuser means supplying low velocity inhalation air to the wearer within the curtain. Air supplied at a single rear inlet connection is split and passes around the sides of the helmet through a double manifold: at the front the rejoined air stream is again split by a perforated partition to supply the high velocity outlet and the low velocity outlet separately. The air curtain member which creates the high velocity curtain is reentrant within the shell of the helmet at its ends, and tabs outside the helmet are provided to limit the forward extent to which the curtain attaches to the wearer''s face.
Inventors
- 👤 Thomas E Rosendahl
- 👤 William J Krisko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:56
CPC Classifications
A; A42; A42B; A42B3/00; A42B3/04; A42B3/18; A42B3/22; A42B3/24; A42B3/0406; A61; A61F; A61F9/00; A61F9/04; A61F9/06; A61F9/068
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
250 words
In an industrial helmet for protecting the wearer against inhalation of air-borne particulate matter, in combination: an impact resistance shell carrying internal suspension means for mounting the helmet on the head of the wearer and comprising crown, front, side, and back portions and a chambered bill portion having a front wall, a perforated top, and a grillwork bottom extending from the rim of said front wall to the rim of said front portion to define the chamber of said bill; an inwardly concave member surrounding said shell and sealed along a top edge to the walls of said shell and along a bottom edge to the front wall of said bill and the side and rear walls of said shell to define a manifold; coupling means for receiving air supplied to said manifold; an air curtain member forming a part of the seal between said manifold and the front wall of said bill, and comprising a strip of material having a plurality of parallel tubular passages extending therethrough and directed downwardly along the front of said bill to provide a high velocity output for air from said manifold in the form of an air curtain encircling the wearer''s face; and diffuser means secured to the grillwork bottom of said bill and the front wall of said shell to provide a low velocity output of air passing through the perforations in the top of said bill from said manifold, whereby to constitute a supply of inhallation air within said air curtain.
Claim 2
Dependent Claim
250 words
In an industrial helmet for protecting the wearer against inhalation of air-borne particulate matter, in combination: an impact resistance shell carrying internal suspension means for mounting the helmet on the head of the wearer and comprising crown, front, side, and back portions and a chambered bill portion having a front wall, a perforated top, and a grillwork bottom extending from the rim of said front wall to the rim of said front portion to define the chamber of said bill; an inwardly concave member surrounding said shell and sealed along a top edge to the walls of said shell and along a bottom edge to the front wall of said bill and the side and rear walls of said shell to define a manifold; coupling means for receiving air supplied to said manifold; an air curtain member forming a part of the seal between said manifold and the front wall of said bill, and comprising a strip of material having a plurality of parallel tubular passages extending therethrough and directed downwardly along the front of said bill to provide a high velocity output for air from said manifold in the form of an air curtain encircling the wearer''s face; and diffuser means secured to the grillwork bottom of said bill and the front wall of said shell to provide a low velocity output of air passing through the perforations in the top of said bill from said manifold, whereby to constitute a supply of inhallation air within said air curtain.
Claim 3
Dependent Claim
28 words
The structure of claim 1 together with tabs depending from said helmet outside said air curtain member for attachment by the high velocity air from said curtain member.
Claim 4
Dependent Claim
19 words
The structure of claim 2 together with resilient means supporting said tabs against outward displacement away from said helmet.
Claim 5
Dependent Claim
30 words
The structure of claim 1 in which the tubular passages of said air curtain member are of smaller diameter in the front of said bill than at the sides thereof.
Claim 6
Dependent Claim
41 words
The structure of claim 1 in which the shell is provided with slits at the bottom of the side walls thereof and said air curtain member is reentrant at its ends, passing through said slits and continuing forwardly inside said shell.
Claim 7
Dependent Claim
28 words
The structure of claim 5 in which the passages in the reentrant portion of said air curtain member are larger than those near the center of the bill.
Claim 8
Dependent Claim
18 words
The structure of claim 1 in which said diffuser means comprises at least one sheet of microperforated metal.
Claim 9
Dependent Claim
23 words
The structure of claim 1 in which said diffuser means comprises a plurality of sheets of microperforated metal having perforations of different sizes.
Claim 10
Dependent Claim
62 words
The structure of claim 1 in which the diffuser means comprises a sheet of microperforated metal having small perforations along the front of said grillwork, sheets of similar metal of larger perforations at the sides of said grillwork, and a sheet of similar metal having still larger perforations at the center of said grillwork next to the front wall of said shell.
Claim 11
Dependent Claim
29 words
The structure of claim 1 in which said manifold includes a partition of honeycomb diffuser material on each side of said helmet to direct the flow of air therethrough.
References Cited (Backward Citations)
US2560215A
Cited
US3822698A
Cited
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 |