US3812812A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Trolling propeller with self adjusting hydrodynamic spoilers
Assignee: Individual
•
Filing: 1973-06-25
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Granted: 1974-05-28
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Expires: 1993-06-25
Abstract
Abstract A marine propeller carrying a plurality of hydrodynamic spoilers formed of elastomeric material which self-deploy at low engine speeds to present maximum effective fluid contacting areas impeding propeller flow, said effective areas being progressively reduced as the propeller speed progressively is increased or its direction of rotation reversed. The propeller manifests a greater-than-normal slip coefficient at low engine speed thus, decreasing the minimum trolling speed without sacrificing performance in reverse or at intermediate and high engine speeds.
Inventors
- 👤 M Hurwitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 04:47
CPC Classifications
B; B63; B63H; B63H1/00; B63H1/02; B63H1/12; B63H1/14; B63H1/28
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
199 words
In combination, a marine propeller having a body including a hub and a plurality of blades connected to the hub, said body having a plurality of spaced slots in selected body portions with said slots extending through said body portions, a hydrodynamic spoiler flap anchored in each of said slots and normally biased to extend laterally of the surface of each respective body portion, each of said spoiler flaps being formed of elastomeric material and having an area of reduced thickness constituting a hinge portion adjacent to and co-extensive in length with a respective slot, the surface of each body portion having a recess adjacent and in trailing relation to a respective slot, each recess being substantially co-extensive in area with each flap to accommodate the flap in substantially flush relationship with the body portion, each slot being formed with a forward leaning angle such that when the propeller is at rest the flaps are inclined into the direction of normal flow which exists when the propeller is rotated in its normal forward diRection, each of said flaps being arranged to assume different angular relationships progressively approaching a respective recess as the rotational speed of the propeller progressively increases.
Claim 2
Dependent Claim
199 words
In combination, a marine propeller having a body including a hub and a plurality of blades connected to the hub, said body having a plurality of spaced slots in selected body portions with said slots extending through said body portions, a hydrodynamic spoiler flap anchored in each of said slots and normally biased to extend laterally of the surface of each respective body portion, each of said spoiler flaps being formed of elastomeric material and having an area of reduced thickness constituting a hinge portion adjacent to and co-extensive in length with a respective slot, the surface of each body portion having a recess adjacent and in trailing relation to a respective slot, each recess being substantially co-extensive in area with each flap to accommodate the flap in substantially flush relationship with the body portion, each slot being formed with a forward leaning angle such that when the propeller is at rest the flaps are inclined into the direction of normal flow which exists when the propeller is rotated in its normal forward diRection, each of said flaps being arranged to assume different angular relationships progressively approaching a respective recess as the rotational speed of the propeller progressively increases.
Claim 3
Dependent Claim
19 words
The invention as defined in claim 1 in which the selected body portions are located on the propeller hub.
Claim 4
Dependent Claim
188 words
In combination, a marine propeller having a body including a hub and blades connected to the hub, each of said blades having a slot extending through said blade, a hydrodynamic spoiler flap anchored in each of said slots and normally biased to extend laterally of the surface of each respective blade, each of said spoiler flaps being formed of elastomeric material and having an area of reduced thickness constituting a hinge portion adjacent to and co-extensive in length with a respective slot, the surface of each blade having a recess adjacent to and in trailing relation to a respective slot, each recess being substantially co-extensive in area with each flap to accommodate the flap in substantially flush relationship with the surface of the blade, each slot being formed with a forward leaning angle such that when the propeller is at rest the flaps are inclined in the direction of normal flow which exists when the propeller is rotated in its normal forward direction, each of said flaps being arranged to assume different angular relationships progressively approaching a respective recess as the rotational speed of the propeller progressively increases.
Claim 5
Dependent Claim
188 words
In combination, a marine propeller having a body including a hub and blades connected to the hub, each of said blades having a slot extending through said blade, a hydrodynamic spoiler flap anchored in each of said slots and normally biased to extend laterally of the surface of each respective blade, each of said spoiler flaps being formed of elastomeric material and having an area of reduced thickness constituting a hinge portion adjacent to and co-extensive in length with a respective slot, the surface of each blade having a recess adjacent to and in trailing relation to a respective slot, each recess being substantially co-extensive in area with each flap to accommodate the flap in substantially flush relationship with the surface of the blade, each slot being formed with a forward leaning angle such that when the propeller is at rest the flaps are inclined in the direction of normal flow which exists when the propeller is rotated in its normal forward direction, each of said flaps being arranged to assume different angular relationships progressively approaching a respective recess as the rotational speed of the propeller progressively increases.
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) | 1977-05-27 | 1977-11-26 | 1978-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-27 | 1981-11-26 | 1982-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-27 | 1985-11-26 | 1986-05-28 | $7700.00 | Window Closed / Lapsed |