Abstract:
An oar consisting of two parallel shafts linked on both ends to form a parallelogram configuration, which keeps the oar&#39;s blade and handle parallel to one another and perpendicular to the boat throughout the rowing cycle. The system is further enhanced to provide an internal, adjustable feathering system, interchangeable handles and blades and an integrated, quick-release oarlock.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   Not Applicable 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT 
   Not Applicable 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a rowing apparatus having an oar and oarlock and particularly to a rowing apparatus having improved efficiency. 
   2. Description of the Prior Art 
   Conventional rowing systems use oars with handles and blades that are solidly fixed to and inline with the oar shaft. An oarlock is positioned about a third of the way down the shaft between the handle and blade. The oarlock acts as a fulcrum about which the oar pivots. As the handle is pulled by the rower, the blade on the opposite end of the oar is pulled through the water in an arc, thereby propelling the boat. 
   As the rower moves the oar through the power stroke, the oar handle and blade are perpendicular to the rower and the boat for a brief instant. Because the most efficient transfer of energy is when the oar pushes against the water perpendicularly with respect to the boat, to improve efficiency and reduce physical stress on the rower it would be advantageous if the angle of the handle and blade always remained perpendicular, regardless of where the oar was in the stroke. 
   Moreover, when resetting the blade at the end of the stroke, the oar is removed from the water and moved backwards to begin the next stroke. During this backward motion, the oar blade is usually “feathered” (turned 90 degrees so that it is parallel to the surface of the water) to reduce wind resistance and to minimize friction should the blade come in contact with the water on the return stroke. 
   Previous inventions that have described the use of universal joints and/or gears to provide feathering systems: Johnson U.S. Pat. No. 1,034,462, Jaeger U.S. Pat. No. 1,909,359, Noogle U.S. Pat. No. 4,738,643, and DuPont U.S. Pat. No. 5,248,272. 
   While these patents describe feathering systems, they do nothing to solve the problem of maximizing efficiency in the oar stroke itself. 
   BRIEF DESCRIPTION OF THE INVENTION 
   The instant invention solves this problem by creating an apparatus that keeps the oar handle and blade perpendicular to the boat at every point in the stroke. 
   The relationship between the orientation of the blade in the water and the boat&#39;s direction of travel is critical to achieving a powerful, efficient stroke. Keeping the blade square to the water as it is pulled through the water reduces power loss due to water sliding off of an angled blade, as is the case in a conventional set-up. 
   Moreover, a new internal feathering system is incorporated into the present invention to enable the rower to “feather” the blade flat above the water on the return stroke to reduce air friction. 
   The benefits of this design are found in the “parallelogram” design, which requires two oar shafts rather than the traditional one in conventional rowing systems. Composite H-Beams (essentially I-Beams turned on their side) are used to reduce weight and increase strength while reducing lateral bending. 
   Finally, the present invention incorporates a system for easily changing the oar&#39;s handles and blades. As mentioned above, maintaining the perpendicular orientation of the handle and blades is accomplished by a parallelogram-like structure with moveable attachment points. The ends of two (long) parallel shafts of equal length are joined at either end by (short) connecting rods that make up a parallelogram. The oar&#39;s handle and blade are attached perpendicularly to the short connecting rods on either end of the long oar shafts. 
   This geometric structure is connected to two stationary pivot points that perform some of the basic functionality of a traditional oarlock. The entire apparatus (integrated oar and oarlock) is mounted on a standard outrigger (as found in most sculls and racing shells) or a custom structure on any boat that can be propelled by oars. 
   When in use, the rower begins his/her power stroke by extending his arms and grasping the handle (sweep oar) or handles (scull) which are perpendicular to the boat. Raising the handles lowers the blades into the water. The rower now pulls on the handles, which cause the blades to be pulled through the water. Both handles and the blades remain perpendicular to the boat and parallel to each other throughout the power stroke. 
   At the end of the power stroke, the rower pushes the handle(s) down thereby raising the blade out of the water. Simultaneously the rower rotates his hands backwards 90 degrees to feather the blade for the return stroke. Again, both handles and the blades remain perpendicular to the boat and parallel to each other throughout the return stroke. 
   Oarlocks serve two primary purposes: to allow the oar to rotate fore and aft about a pivot point and to allow the oar shaft to pivot up and down, which allows the oar blade to be lowered into and raised out of the water. The pivot points in the present invention are located in the traditional location, approximately ⅓ of the way down the shafts when measured from the handle. The dual shaft design of the parallelogram requires two pivot points as opposed to the single pivot point in a traditional oar and oarlock design. Further, the oarlock in the current invention is integrated into the oar shafts as opposed to being a separate component mounted on the boat gunwales or outrigger. 
   There is also a swivel bearing present in the middle of the oarlock, between the two main oar shafts to provide support for the feathering rod. 
   The conventional rowing system has fixed handles and blades. This invention incorporates the ability to quickly change handles and blades. This capability is a real advantage when wanting to use different blades and/or handles for different purposes (racing or recreation) or conditions (smooth water or choppy). It also allows rowers to replace damaged components more easily than with the now used one-piece design. 
   The handle and oar share common attachment hardware. They are both physically attached to the internal feathering system that resides within the parallelogram shaft structure. 
   Finally, as mentioned above, the system allows the rower to keep the oar handle perpendicular to the rower. 
   It is an object of the present invention to provide an oar design, both sweep and scull) of improved efficiency by keeping the handle and blade perpendicular to the rower and direction of travel of the boat at all times. 
   It is a further object of the present invention to provide a method for adjusting the oar&#39;s leverage by changing the position of the oar relative to the oarlock. 
   It is a further object of the present invention to provide an integrated oarlock that can be easily attached to and removed from standard gunwales or outriggers and permits free movement of the oar assembly in two axes. 
   It is yet a further object of the present invention to provide a means for feathering the blade (twisting the oar handle 90 degrees on the return stroke to cut down on air/water resistance of the blade). 
   It is another object of the present invention to provide an adjustment for the “attack” angle of the blade on the power stroke and the “feathering” angle of the blade on the return stroke. 
   The present invention also improves the state of the art by incorporating a system for easily changing the oar&#39;s handles and blades. Traditional oars make no provisions for interchanging handles and blades of different sizes and shapes. To change the handle and/or blade, the oar itself usually must be changed. It is further the object of the present invention to provide a method for increasing the stiffness and reducing the weight of the oar shafts. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1   a  is a top schematic view of the new design at the beginning of the power stroke. 
       FIG. 1   b  is a top schematic view of the new design at the middle of the power stroke. 
       FIG. 1   c  is a top schematic view of the new design at the end of the power stroke. 
       FIG. 2  is a perspective view of the new oar. 
       FIG. 3  is a detail of the oarlock system. 
       FIG. 4  is a side view of the oar system. 
       FIG. 5  is a top view of the oar system. 
       FIG. 6   a  is a side view of the vertical oar movement about the oarlock with the blade raised. 
       FIG. 6   a  is a side view of the vertical oar movement about the oarlock with the blade horizontal. 
       FIG. 6   c  is a side view of the vertical oar movement about the oarlock with the blade lowered. 
       FIG. 7   a  is a perspective view of the feathering system with the oar shafts not shown and the blade in the fully feathered position. 
       FIG. 7   b  is a perspective view of the feathering system with the oar shafts not shown and the blade in the partially feathered position. 
       FIG. 7   c  is a perspective view of the feathering system with the oar shafts not shown and the blade in the fully unfeathered position. 
       FIG. 8  is an exploded view of the entire oar system. 
       FIG. 9  is a perspective view of the preferred oarlock. 
       FIG. 10  is a top view of the preferred oarlock. 
       FIG. 11  is a front view of the preferred oarlock. 
       FIG. 12  is a side view of the preferred oarlock. 
       FIG. 13  is a perspective of the view of the feathering system showing the blade fully unfeathered. 
       FIG. 14  is an enlarged detail of the feathering rod connection to the handle. 
       FIG. 15  is an enlarged detail of the feathering rod connection to the blade. 
       FIG. 16   a  is a front view of the end connectors showing the blade angle adjustment pins and the handle stops of a first embodiment in the fully feathered position. 
       FIG. 16   b  is a front view of the end connectors showing the blade angle adjustment pins and the handle stops of a first embodiment in the partially feathered position. 
       FIG. 16   c  is a front view of the end connectors showing the blade angle adjustment pins and the handle stops of a first embodiment in the fully unfeathered position. 
       FIG. 17  is a perspective view of one of the oar system&#39;s H-beams. 
       FIG. 18  is a top view of one of the oar system&#39;s H-beams. 
       FIG. 19  is a side view of one of the oar system&#39;s H-beams. 
       FIG. 20  is an end view of one of the oar system&#39;s H-beams. 
       FIG. 21   a  is a front view of the preferred embodiment of handle stops for the feathering system, showing the adjustment stop in a first position and the bolt upright. 
       FIG. 21   b  is a front view of the preferred embodiment of handle stops for the feathering system, showing the adjustment stop in a second position and the bolt upright. 
       FIG. 21   c  is a front view of the preferred embodiment of handle stops for the feathering system, showing the bolt in a rotated position and the lower stop in a first position. 
       FIG. 21   d  is a front view of the preferred embodiment of handle stops for the feathering system, showing the bolt in a rotated position and the lower stop in a second position. 
       FIG. 22  is a cross-sectional view of the preferred embodiment of the feathering system universal joint connection to the handle. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now to  FIGS. 1   a ,  1   b .  1   c ,  2  and  3 , the new oar system is shown. The oar system is made up of a handle  1 , a pair of oar shafts  2 , of equal length; two end connectors  3  and a blade  4 . Note that the oar shafts are pivotably attached to the end connectors so that as the handle is moved, the oar shafts move about to create a parallelogram configuration, as shown in  FIGS. 1   a ,  1   b  and  1   c . An oarlock  5  is shown at a central point. The oarlock  5  allows the oar shafts to rotate as shown. The oarlock also allows the oar to move vertically, as discussed below. The oarlock  5  is shown in its preferred position, which is about ⅓ of the way down the shaft from the handle. However, the oarlock  5  can be positioned at other places along the shaft (if desired). See, e.g.,  FIGS. 4 and 5 . 
   In  FIG. 1   a , the direction of the rower and the direction of the travel of the boat are indicated by the arrows. The rower pulls rearward on the handle  2  (as indicated by the arrow). At the beginning of the stroke, the handle is fully forward, the oar shafts are at a 45-degree angle with respect to the centerline of the rower and the blade is fully back and positioned perpendicularly to the boat. 
   When in use, the rower begins his/her power stroke by extending his arms and grasping the handle (sweep oar) or handles (scull) which are perpendicular to the boat. Raising the handles (see,  FIG. 6   c ) lowers the blades into the water. The rower now pulls on the handles, which cause the blades to be pulled through the water. Both handles and the blades remain perpendicular to the boat and parallel to each other throughout the power stroke.  FIG. 1   b  shows the oar system in the middle of the stroke. Here, the handle, shafts and blade are aligned in a straight line. 
     FIG. 1   c  shows the end of the power stroke. Here, the handle is fully back, the blade is fully forward (and perpendicular to the boat) and the oar shafts are at a 45-degree angle with respect to the centerline of the rower (albeit at the opposite angle with respect to  FIG. 1   a ). At the end of the power stroke, the rower pushes the handle(s) down thereby raising the blade out of the water. Simultaneously the rower rotates his hands backwards 90 degrees to feather the blade for the return stroke. (The feathering system is discussed below). Again, both handles and the blades remain perpendicular to the boat and parallel to each other throughout the return stroke. 
     FIGS. 2–3  details of the oarlock used with cylindrical oar shafts. 
     FIG. 2  is a perspective view of the new oar showing the position of the oarlock  5  with respect to the oar shafts. Note that the oarlock system can use the clamps  6  (for a round oar shaft) shown in  FIGS. 2–5 , or a pin system (for the preferred H-beam shaft), shown in  FIGS. 9–12  (discussed below). Note also that clamps can be used with the H-beam as well, although they are not preferred. 
     FIG. 3  is a detail of the oarlock system that uses round shafts for the oars. Here, clamps  6  secure the oar shafts  2  to the pivot body  7 . The clamps are rotatably attached to the pivot body  7  so that the oar shafts are free to turn about the pivot body (see, e.g.,  FIGS. 1   a  and  5 ). The pivot body is secured to a bracket  8  by pins  9 , that permit the pivot body to rotate about the bracket (see. e.g.  FIGS. 3 and 6   a – 6   c ). 
     FIG. 4  is a side view of the oar system that shows the vertical movement of the oar shafts  2  with respect to the bracket  8 . This movement is caused by the pivot body pivoting on the pins  9 . Note also that the shafts can be positioned left or right of the position shown. This movement affects the leverage of the rower. Moving the shaft left, increases the leverage but decreases the stroke and vice versa. 
     FIG. 5  is a top view of the oar system that shows the angular movement of the oar shafts  2  about the oarlocks. 
     FIGS. 6   a – 6   c  are schematic views of the vertical oar movement about the oarlock. In  FIG. 6   a , the blade  4  is angled upward. This is accomplished by pivoting the pivot block.  FIG. 6   b  shows the oar in the neutral position and  FIG. 6   c  shows the blade of the oar in the downward position. 
     FIG. 7   a  is a detail view of the feathering system showing the blade fully feathered. The feathering system uses a feathering rod  10  that is attached to the handle by a first universal joint  11  and to the blade by a second universal joint  12 .  FIG. 7   b  is a detail view of the feathering system showing the blade partially turned for a power stroke. Here, the handle  1  has been turned (see the register mark  13 ). As the handle is turned, the feathering rod  10  is turned as well. This, in turn, causes the blade  4  to turn as shown.  FIG. 7   c  is a detail view of the feathering system showing the blade fully turned for a power stroke. As shown, the register mark  13  is now vertical as is the blade. 
     FIG. 8  is an exploded view of the entire oar system of the preferred embodiment. The handle  1  is attached to the feathering rod via universal joint  11   a  and  11   b  through the end connector  3  (note both end connectors are identical). It is supported by a bushing  20 . The end connector has two brackets  21  that secure the ends of the oar shafts and support bushing  20 . The oar shafts (as discussed below) have flat ends that are held to the brackets  21  by  22 , loosely to permit free rotation of the shafts during each stroke. In between the two oar shafts  2  is the feathering rod  10 . At each end of the feathering rod  10  is one half of a universal joint  11   a  and  12   a . The other half of the universal joints  11   b  and  12   b  are attached to the end of the handle and the blade respectively. The other ends of the oar shafts are attached to the end connector  3  at the blade end of the oar. Finally, the blade  4  is attached to the feathering rod using the universal joint  12   a , as shown. The pivot body  19  of the oarlock  15  is attached to the oar shafts, as discussed above, while the oar shafts are attached by the pins  17 . 
     FIG. 9  is a perspective view of the preferred embodiment of the oarlock  15 . This embodiment uses oar shafts formed of an H-beam construction (as discussed below). Because the oar shafts have a flattened center portion, the clamps  6  are replaced by pins  17 . Spacers  18  are used to reduce friction between the pins and the oar shafts  2 . Shoulder bushings  18   a  are used as additional spacers to accommodate the side flanges on the oar shafts. The pivot body  19  is shown in a neutral position. The pivot body has a generally rectangular upper portion and two side flanges. The pivot pins  9  are secured to these flanges. The bracket  8  has a flat base as shown. A bolt  13  attached the bracket  8  to a collar that attaches to an outrigger (not shown). 
     FIG. 10  is a top view of the oarlock.  FIG. 11  is front view of the preferred the oarlock showing the feathering rod support  16 . In the center of the pivot body  19  is a threaded hole  16   a  that holds a support  16  for the feathering rod  17  (discussed below). The feathering rod support is positioned between the oar shafts.  FIG. 12  is an end view of the preferred oarlock showing the pivot body slightly tilted in the bracket. 
     FIG. 13  is a detail of the feathering rod connection the blade similar to  FIG. 7   c.    
     FIG. 14  is an enlarged view of the connector  3  on the handle end, showing details of the feathering system. 
     FIG. 15  is an enlarged view of the connector  3  on the blade end, showing details of the feathering system. 
     FIGS. 16   a – 16   c  are detail views of the end connector showing the blade angle adjustment pins and stops on the handle and the relationships of the handle and blade. In  FIG. 16   a  the system for limiting and adjusting the blade consists of a blade angle adjustment pin  25  that extends through the base of the handle universal joint  11   a  on the inside of the end connectors and two blade angle adjustment stops  26 . These stops are semi-circular and are positioned adjacent to the blade angle adjustment pin. When the blade reaches the desired feathering angle on the return stroke, the blade angle adjustment pin  25  is stopped by the blade angle adjustment stops  26 . Similarly, when the rower turns the oar handle  2  counterclockwise at the beginning of the power stroke, the blade angle adjustment pin  25  is stopped by the blade angle adjustment stops  26  when the desired attack angle has been reached 
   Once the desired angles have been selected, the blade angle adjustment stops are locked down by tightening two locking nuts (not shown) that fix each of them to the inside of the end connectors. Additional adjustment is possible by adding eccentric cam heads to the adjustment pins  25  as shown in  FIG. 16   c.    
     FIGS. 16   b  and  16   c  show the movement of the handle and blade as well as the operation of the stop. 
     FIGS. 16   a–c  show one embodiment of handle stop and universal joint connection. While the multiple spacing holes provide versatility in adjusting the stop movement, a simpler design is preferred.  FIGS. 21 and 22  show the preferred embodiments for the handle stop and universal joint for the feathering system. This embodiment is preferred because it is simpler to build and use than the embodiment of  FIGS. 16   a – 16   c.    
     FIG. 21   a  is a front view of the preferred embodiment of handle stops for the feathering system. In this embodiment, the multiple spacing holes  27  are removed and replaced with a pair of holes. Moreover, the arced member  25  is eliminated. A threaded bolt  40  passes through the handle end  42  of the universal joint  41 . The top of the bolt  40  has an elongated flat surface  43 , which is designed to make contact with the stop pins  44   a  and  44   b . Pin  44   a  is a bolt that is threaded into the end block. It can be secured by a lock nut, if desired. The pin  44   b  is an eccentric bolt. It too is threaded into the end connector as shown and is secured by a locknut  45 . The eccentric head of the bolt allows the user to make fine adjustments of the feathering system. As shown in  FIG. 21   a , the bolt  40  is upright and the bolt  44   a  is shown in a first position, which allows the bolt  40  to move to a position that contacts the side of bolt  44   a . In  FIG. 21   b , the bolt  44   a  is turned 180 degrees. Here, the bolt  40  cannot be turned as far as in the position of  FIG. 21   a . This allows the user to make precise adjustments to the feathering system, as the bolt  44   a  can be set to any position between those shown in  FIGS. 21   a  and  21   b.    
     FIG. 21   c  is a front view of the preferred embodiment of handle stops for the feathering system, showing the bolt  40  in a rotated position and the lower stop  44   b  in a first position.  FIG. 21   d  is a front view of the preferred embodiment of handle stops for the feathering system, showing the bolt  40  in a rotated position and the lower stop  44   b  in a second position. As before, the cam action of the bolt  44   b  allows fine adjustment of the position of the bolt  40  at its ending positions. 
     FIG. 22  is a cross-sectional view of the preferred embodiment of the feathering system universal joint connection to the handle. Here, the handle  1  has a threaded end portion  1   a  that passes through the end connector  3 . A bushing  20  can be used to reduce the friction in the end connector is desired. The threaded portion  1   a  of the handle is then screwed into the handle end  11   a  of the universal joint  11 . As mentioned above, the stop bolt  40  is threaded through both the handle end of the universal joint and the threaded end of the handle. The universal joint  19  has a pin that connects the handle end  11   a  to the feathering rod end  11   b . The feathering rod  10  also has a threaded end  10   a  that screws into the universal joint as shown. A lock nut  55  is used to secure the feathering rod in the universal joint to ensure that the rod does not turn except when moved by the handle. 
   The feathering rod plays an important role in holding together the oar handle and blade. Finding the correct length of the feathering rod is necessary in order to achieve the optimal balance between friction and free play. The adjustment mechanism for altering the length of the feathering rod is the use of threads of opposite direction on either end. One end of the feathering rod has right-hand threads attaching it to the Universal Joint  11   b  and the other has left-hand threads attaching it to the other the Universal Joint  12   b . Therefore turning the feathering rod one way will lengthen the rod and turning it in the other will shorten it. When the proper adjustment is achieved, lock nuts are used to insure that the rod does not turn relative to the universal joints. 
   As discussed above, the preferred embodiment uses an H-beam construction for the oar shafts.  FIG. 17  is a perspective view of one of the oar system&#39;s H-beams. As mentioned above, in the preferred embodiment, the oar shafts are H-beams.  FIG. 18  is a top view of one of the oar system&#39;s H-beams.  FIG. 19  is a side view of one of the oar system&#39;s H-beams.  FIG. 20  is an end view of one of the oar system&#39;s H-beams. The oar shaft has a center web  30  that has two curved ends  31  as shown. The curved ends have holes  32  to permit the oar shaft to be attached to the end connectors, as described above. Two flanges  33  are formed on the sides of the center web to complete the H-beam form. Note that the flanges do not extend to the curved ends. This is done to permit the curved ends to rotate in the brackets as the oar is operated.  FIG. 17  shows the center of the oar shaft. Here, three holes  34  are shown. These holes are used to attach the oar shaft to the oarlock. The three holes allow for position adjustment of the oar shaft on the oarlock as is needed to adjust the leverage/stroke. 
   In the present invention, the oar handle and blade are easily removed by removing the blade angle adjustment pin from the universal joint and unscrewing the threaded handle and/or blade. By removing the pin(s), the handle and/or blade can be removed and replaced with ones of different sizes or shapes. 
   High efficiency oars must be both stiff and lightweight in order to perform. This is especially important in the present invention since two shafts are required for each oar in addition to other components that are not needed on standard “one-piece” oars. Carbon fiber or some other strong, lightweight composite material is recommended for the oar shafts, as they are both stiff and lightweight. Further, it is recommended that the shafts utilize an “H-Beam” (I-Beam lying sideways) to further increase the stiffness while keeping the mass to a minimum. 
   It should be noted that the shaft&#39;s material and shape represent the preferred embodiment. Shafts made of other material (wood, aluminum, plastic, etc.) and shapes, (round, square, rectangular, triangular, etc.) can also be used. 
   The present disclosure should not be construed in any limited sense other than that limited by the scope of the claims having regard to the teachings herein and the prior art being apparent with the preferred form of the invention disclosed herein and which reveals details of structure of a preferred form necessary for a better understanding of the invention and may be subject to change by skilled persons within the scope of the invention without departing from the concept thereof.