Oar

Loerch, Mark P.;

The oar disclosed herein is re-enforce by a stay which is anchored at both ends of the oar shaft and is supported near the oar lock location by a brace. The two points, where the stay emanates from the oar shaft, lie in the same plane as a set of points at the tip of the brace. The points, that define the aforementioned plane may be aligned to form a triangle. The triangle is assigned a vertex near the tip of the brace. When the oar blade is normal to the water surface during an oar stroke, the vertex of the aforementioned triangle points downwardly with respect to the force direction of the blade in the water. The stroke forces thereby produce a moment that tends to unfeather the oar blade. The unfeathering of the oar blade must be arrested by an oar lock as soon as the blade surface becomes normal to the water surface. To maintain the oar blade in the proper position during the stroke requires no handle torque as long as the oar lock of the oar is equipped with a stop to prevent further unfeathering of the oar.

BACKGROUND

This invention relates to sculling oars that are re-enforced with stays and braces, and specifically to any oar for which the blade force and the handle force do not intersect the feathering rotation axis of the oar during the stroke.

The following U.S. patent defines a mechanism which would appear to be germane to the patentability of the disclosed invention:

No. 231,016 M. F. Davis, Aug. 10, 1880

The patent of Davis teaches that the handle centerline of an oar may be offset from the feathering rotation axis to counteract the moment that is produced during the stroke when the larger portion of the oar blade is below the feathering rotation axis of the oar.

In the disclosed invention, a brace and a stay are mounted to the oar shaft in such manner as to bow the ends of the oar shaft toward the brace. If the oar blade is oriented so that the blade force acts above the feathering rotation axis during the stroke, the force will tend to feather the oar. The oarsman may apply a counter-moment at the oar handle in order to eliminate the feathering tendency of the oar. Alternatively, if the oar blade is oriented so that the blade force acts below the feathering rotation axis, the force will tend to unfeather the oar. The unfeathering of the oar is desirable during the stroke as long as an oar lock stop is provided to properly orient the oar blade.

SUMMARY

An object of this invention is to provide an improved oar of lightweight construction with exceptional stiffness. This is accomplished by means of a stay which is anchored near both ends of the oar shaft and is supported near the oar lock rotation by a brace. A second object is to create during the stroke a force system, in which the oar blade surface, being normal to the water surface, tends to unfeather the oar and to hold the oar shaft against a stop of an oar lock. This is achieved by the downward angling of the stay and brace alignment from the blade force direction.

DRAWINGS

FIG. 1 is a top view of the oar in the normal position.

FIG. 2 is a top view of the oar after the oar has been rotated to the feathered position.

FIG. 3 is a top view of the guide.

FIG. 4 is the view of FIG. 1 with a sectional view of the guide broken away from the brace. The guide has been sectioned at line 160, 160 of FIG. 3.

FIG. 5 is an enlarged sectional view of the guide and brace. The guide and brace are sectioned at line 160, 160 of FIG. 3.

FIG. 6 is an enlarged end view of the oar with the jacket having been deleted in order to emphasize the shaft of the oar.

FIG. 7 is an enlarged perpsective view of the handle end of the oar.

FIG. 8 is an enlarged perspective view of the blade end of the oar.

DESCRIPTION

The oar shaft comprises a slender column 01. A brace 10 emanates from the column 01 and is adjacent to the part of the column where an oar lock is to be mounted 09. The brace 10 is fixed to the column 01. The end of the column 01 nearest the brace 10 may be fitted to the socket 31 of a handle grip 30, and the end of the column 01 farthest from the brace 10 is fitted to the socket 33 of an oar blade 32. A stay 13 originates at the blade end of the oar 03, passes through a guide 12 at the tip of the brace 11 and terminates at the handle end of the oar 02. The column 01 of the oar shaft is bowed toward the brace 10. The two points 25, 26, where the stay 13 emanates from the column 01 of the oar shaft, lie in the same plane as the set of points 27, 28 through which the stay 13 passes at the tip of the brace 11.

The stay 13 may be secured to the column 01 of the oar shaft in any suitable manner. The present example includes a stay 13 that passes through two holes 05, 06, on one side of the column 01 of the oar shaft. One hole 05 is located at the handle end of the oar shaft 02 and passes through the shaft facing 07 at the handle end of the column 01. The other hole 06 is located at the blade end of the oar shaft 03 and passes through the shaft facing 08 at the blade end of the column 01. The ends of the stay 15, 16, pass through the holes on the side of the oar shaft and extend beyond the shaft facings 07, 08, at each end of the column 01. The stay 13 is captured to the column 01, by separated retainers 17, 18, at each end of the stay 13.

• Address generation system Valve disabling mechanism
• Dowel drill fixture Liquid jet recorder
• Method of drying fibrous structures Estrogen receptor-.beta. ligands
• Polymer film heat exchanger Equipment support pad and method
• Airblast fuel injector Sweetener composition
• Trisaryl-1,3,5-triazine ultraviolet light absorbers Crankshaft-forming apparatus and method
• Concentric pipe coupling Open end spinning apparatus
• Strip casting apparatus Chloro-pyridinyloxymethyl esters of thiocyanic acid
• Constant drag device Collapsible drying rack
• Hair fashion accessory Wick bar lift
• Electrical conductor interconnection apparatus Data compression apparatus and method
• Proximity sensing shower system Process of forming contact holes
• Nursing bottle holder Cabinet hinge
• Soldering appearance inspection apparatus Scanning optical rangefinder
• Digital error detection using bracketing Friction force measurement apparatus
• Linear alpha olefin production Impact absorbent shifting device
• Lithographic printing process User-interface for a projection device
• Storage page for three-dimensional items Dispensing instrument with supported balloon
• Energy-absorbing bumper assembly Heat exchanger and brazing method
• Roll fuser stripping mechanism Apparatus for bagging product units
• Floral container Tire rim holder
• NMR measurement on frozen cores Pipeline rehabilitation articulated gasketed-joint pipe
• Lightweight impact resistant helmet system Cross-connecting sub-time slot data rates
• Compact disc case IDE interface adapter
• Luminescence device and display apparatus Carton with handle
• Non-insulating DC--DC converter Enhanced subscriber IP alerting
• Variable length columns Automatically controlled washing machine
• Prostaglandin synthase-2 inhibitors Analgesic heterocyclic compounds
• Magnetic resonance imaging system Proxy session count limitation
• Method of restructuring bone Vaginal douching and/or enteroclysm device
• Image reading apparatus Optical fixing toner
• Apparatus for heating food-warmer plates Culinary product with creaming powder
• Multipurpose prying tool External heat engine
• Electrical receptacle Treatment of concentrated phosphoric acid
• High frequency linearizer Collapsible bucket
• Microtitration system Optical fiber array
• Chemical vapor deposition of titanium Slidable storage wall-mount
• Surface marking device and method Foreign exchange ready reckoning chart
• Mismatched compression glass-to-metal seal Protective filter lenses
• Fuel compositions Pipe sleeve
• Crutch having a changeable armpiece Fifth wheel
• Electronic endoscope apparatus Self-propelled overhead track-mounted moving system
• Doll plus invertable container Scoring tool
• Adjustment and/or alignment arrangement Chip antenna for terrestrial DMB
• Appetite stimulating pyrrolo[2,1-b][3]benzazepines

Another feature of the oar shaft includes a jacket 52 that surrounds the oar shaft. The jacket 52 is comprised of material that floats in water.

OPERATION

The stay 13 and brace 10 bow the column 01 of the oar shaft and offset the blade 32 from the feathering axis of the oar 60. The guide 12 at the tip of the brace 11 holds the stay 13 on the brace 10. The plane, that has been defined previously by a set of points 27, 28, at the tip of the brace 11 and by the stay's two points of origin 25, 26, on the oar shaft, can be used as a reference for positioning the stay 13 and the brace 10 on the oar. The points that define the aforementioned plane 25, 26, 27, 28, may be aligned to form a triangle 20, 21, 22. The triangle 20, 21, 22, is assigned a vertex 23 near the tip of the bracket 11. When the oar blade 32 is normal to the water surface during an oar stroke, the vertex 23 of the aforementioned triangle 20, 21, 22 points downwardly with respect to the force direction of the blade 32 in the water. The downward angling of the aforementioned plane and of the triangle 20, 21, 22, therein results in the force of the blade 61 being located below the feathering axis 60 of the oar. Because of the location of the force of the blade 61 with respect to the feathering axis 60, a moment is created that tends to unfeather the oar. The tendency of the oar to unfeather may be arrested by an oar lock as long as a stop is provided in the oar lock to properly orient the oar blade 32 in the water. Proper orientation of the oar blade 32 is attained as soon as the blade 32 becomes normal to the surface of the water. However, an oarsman may orient the oar blade 32 during a stroke so that the force direction of the oar blade 61 acts above the feathering axis of the oar 60. The oar has the tendency in this case to feather. The oarsman must apply a sufficient countermoment before the catch in order to eliminate the feathering tendency of the oar. Unfeathering tendency of the oar is therefore always desirable as long as the oar is equipped with an oar lock of the type previously described.

The stay 13 and the brace 10 prevent bending stresses from occurring in the oar shaft column 01 during propulsion. The slender oar shaft column 01 is stronger in compression than in bending, and undergoes compressive stress as the blade of the oar 32 is drawn aftward through the water. The brace 10 also functions as a compression member and absorbs the forces that are exerted by the stay 13. The stay 13 undergoes tensile stress throughout the stroke and partially absorbs the forces that are created by the resistance of the aftward movement of the oar blade through the water.

In the previously described method for anchoring the stay 13 to the oar shaft column 01, the retainers 17, 18 maintain tension in the stay 13 and capture the stay 13 to the oar shaft column 01. The capturing of the stay 13 to the oar shaft column 01 prevents the stay 13 from sliding through the holes 05, 06, in the column 01.

The jacket 52 allows the oar to float in water. Flotation of the oar in water is accomplished by maintaining a buoyant effect. The jacket 52 is therefore comprised of a suitable buoyant material. The jacket 52 covers the oar so that the oar shaft column 01 is surrounded with the aforementioned buoyant material. Due to the tubular shape of the jacket 52 and the buoyant material thereof, the jacket 52 may be located at different points along the oar shaft column 01.

While the above description contains many specifications, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of one preferred embodiment thereof. Many other variations are possible. For example, some of these variations include an oar shaft having a cross-section of any suitable shape, an oar shaft having any number of methods for anchoring a stay. Accordingly, the scope of the invention should be determined not by the embodiment illustrated, but by the appended claims and their legal equivalents.