US3037219A - Folding blade for an oar or paddle - Google Patents

Description

June 5, 1962 J. c. WEBB FOLDING BLADE FOR AN OAR OR PADDLE Filed Aug. 51, 1959 INVENTOR. (fa/222 6'- M56 BY mad q Zs/ United States atent 3,037,219 Patented June 5, 1962 Free 3,037,219 FOLDING BLADE FOR AN OAR R PADDLE John C. Webb, 7 Verona Drive, Riverside, Conn. Filed Aug. 31, 1959, Ser. No. 837,212 13 Claims. (Cl. 9-24) The invention relates to a folding oar or paddle, and more particularly to the folding blade for such an oar or paddle.

Folding oar blades have previously been proposed to achieve two main objectives, namely, to reduce the storage space required for the oars, and to facilitate rowing. During the backward stroke of the oar relative to the boat movement, hereinafter referred to as the power stroke, it is desired that the oar present to the water the largest possible surface transversely of the direction of the stroke. During the forward or return stroke, it is either necessary to lift the blade of the oar from the water, or to turn the oar in such a manner that the broad faces of the oar extend substantially in the direction of oar movement, and one of the narrow edge faces is exposed to the resistance of the water. Lifting the oar during alternate strokes consumes much energy. Turning the oar or paddle after each stroke requires a skill not commonly possessed.

It was previously proposed to divide the blade of an oar into several portions and to connect the several portions to each other and to the shank portion of the oar by hinges, various devices being provided to utilize the resistance of the water to the movement of the oar for spreading and folding the oar blade during the power stroke and the return stroke respectively. As far as these devices were applied to rigid paddles of wood, the hinge mechanism added weight to a structure which was inherently heavier than is desirable. Folding of the several blade portions made it impossible to achieve a structure which would have the most desirable hydrodynamic properties both in the spread and the folded condition. Replacing rigid wood portions by more or less rigid frames covered with light fabric went far to overcome the undesirable weight characteristics of known folding oars without resulting in a truly satisfactory hydrodynamic design.

A principal object of the invention is the provision of an oar or paddle which may be moved through its power stroke and the subsequent return stroke without lifting it from the water, and which assumes two different shapes during the two strokes, the shapes being adapted to the different hydrodynamic requirements of power and return operation respectively.

More specifically, the invention aims at providing a blade shape during the power stroke which oifers a maximum resistance to the flow of water so as to propel a boat with maximum force for a given blade size, and a different blade shape during the return stroke which minimizes drag and avoids the formation of vortices about the blade so that the return stroke does not cancel any appreciable portion of the eifort spent during the power stroke.

These principal objects are to be achieved with an oar which can be compactly folded when not in use so as to occupy but very little storage space, and which may be constructed from light weight materials so as to be transported without effort.

An additional object of the invention is the provision of an oar or paddle of the type described which can easily be operated by one unskilled in rowing with high efficiency.

Another object is the provision of an oar or paddle blade which is of simple and rugged construction so as to withstand rough handling, and to have a long useful life.

The present invention is based on careful observation of the feet of water fowl and translates the mechanical principles of the web foot of these birds into a structure capable of achieving the objects sought in a folding oar, and particularly in a folding blade for an oar or paddle which has utility not only in propelling a boat in water, but may find applications Wherever a liquid is to be moved in a preferred direction by a reciprocating member immersed in the liquid.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which like reference numerals designate like parts throughout the figures thereof, and wherein:

FIG. 1 is a front view of a preferred embodiment of the invention attached to a boat and in the position assumed during the power stroke of the oar;

FIG. 2 shows the device of FIG. 1 in fragmentary side view in the position assumed during the return stroke of the oar;

FIG. 3 is a top view of the device of FIG. 2;

FIG. 4 is a fragmentary sectional front elevation of the device of FIG. 3 the section being taken on line 44;

FIG. 5 is a front view of the device of FIG. 1 in the storage position; and

FIG. 6 is a transverse sectional view of the device of FIG. 2 taken on the line 6-6.

Referring now to the drawing, and first to FIG. 1, there is shown the shank portion 11 of an oar which is integral with the central rib 15 of the oar blade. A connecting member 12 projects transversely from the shank portion 11 in a forward direction and is secured to the shank portion by a transversely extending hinge 13. The blade of the oar is fastened to the connecting member 12 and includes two lateral ribs 14 which are mounted on the connecting member 12 by means of two pivot pins 16. When the hinged connecting member 12 extends perpendicularly from the shank portion 11, as shown in FIG. 1, the lateral ribs 14 extend in a common plane substantially parallel to the longitudinal axis of the shank portion 11 and the pivotal movements of the ribs 14 take place in planes substantially perpendicular to the direction of elongation of the hinge 13.

A web 18 of pliable substantially waterproof material such as coated fabric is fastened to the lateral ribs 14 and the central rib 15 by means of nails 22. The web is cut in such a manner that the lower edge portion 19 thereof is taut when the lateral ribs are spread apart about their respective pivot pins 16 Whereas the upper portion of the web 18 is slack.

When the lateral ribs 14 and the connecting member 12 assume the positions indicated in FIG. 1, the oar blade is ready for the power stroke (first position). The face of the web 18 seen in FIG. 1 is directed against the water during this stroke. The pressure of the water against the slack portion of the Web 18 gives each symmetrical half of the blade a concavely curved shape, the curvature being both lengthwise and transverse so that the blade forms a scoop offering maximum resistance to the water. The water pressure against the transversely concave web tends to spread the lateral ribs 14 apart so that the position of the blade illustrated in FIG. 1 is maintained during the power stroke of the oar.

The position of the elements of the oar blade during the return stroke is illustrated in fragmentary side view in FIG. 2 (second position). During the return stroke, the back side of the central rib forms the leading edge of the blade and the pressure of the water against the back of the web 18 causes the connecting member 12 to pivot counterclockwise about the hinge 13 as seen in FIG. 2. The same pressure also causes the lateral ribs 14 to pivot toward each other about their respective pins 16 so that the web folds substantially along the longitudinal axis of the central rib 15 and the two folded halves extend in the same direction from the central rib 15, with the free ends of the lateral ribs closely adjacent each other. In this position, the blade offers minimum resistance to the flow of water about it and the formation of vortices, which would dissipate the energy spent during the power stroke, is largely avoided.

FIG. 2 shows a lateral extension 21 on the shank 11 where the central rib 15 starts. This lateral extension provides a reinforced support for the hinge 13. It has an abutment face which cooperates with a mating abutment face 20' on the connecting member 12 to stop the connecting member in the position illustrated in FIG. 1 during the power stroke of the oar.

FIG. 2 also shows that the front faces 23 of the ribs are longitudinally curved in a concave manner. This curvature which is also assumed by the portions of the web 18 secured to the front faces 23 contributes greatly to the desirable hydrodynamic properties of the blade during the power stroke without influencing the shape of the blade during the return stroke in any significant manner.

It is seen from FIG. 2 that the top ends of the lateral ribs 14 are spaced forward from the central rib 15, and this is still better seen from FIG. 3 which shows a top view of the device of FIG. 1. The top ends of the ribs define a triangle two sides of which are closed by the web 18 whereas the forward side is open. While the free ends of the ribs 14 are closely spaced together during the return stroke of the car, the top or connected ends of the lateral ribs are spaced from each other and from the central rib 15 at all times.

As best seen from FIG. 4 which shows a fragmentary section of the device of FIG. 3, the pivotal movement of the lateral ribs is limited in both directions by abutment of the ribs against the edges 17 of respective openings in the connecting member 12 in which the ribs are mounted by means of the pivot pins 16. Outward movement of the lateral ribs would also be restrained by the tension in the lower edge portion 19 of the web 13 when the blade is spread, but it is preferred not to have the relatively weak fabric absorb the entire force of the power stroke. This greatly increases the useful life of the web.

Abutment of the ribs 14 against the inner edges 17 of the connecting member 12 ensures symmetrical positioning of the lateral ribs during the return stroke of the oar. This feature contributes to low drag losses of energy.

When the oar is removed from the water and held in an upright position, the lateral ribs follow gravity and the blade collapses to assume the shape shown in front view in FIG. 5 (third position). The free ends of the lateral ribs 14 and of the central rib 15 are gathered closely together. This position also is most advantageous for storage of the oar since it requires but a minimum of space. It will be appreciated that the shank portion 11 may be made of several longitudinally connecting pieces capable of being readily disassembled in a well known manner if storage in a very short space should be desirable.

FIG. 6 illustrates the manner in which the web 18 is fastened to the lateral ribs 14 and central rib 15. In the collapsed position of the blade illustrated, the web forms folds on either side of the central rib. These folds are partially, though not entirely, taken up when the lateral ribs jointly swing away from the central rib 15 by move ment of the connecting member 12 about the hinge 13 during the return stroke of the oar. The uppermost portion of the web 8 is preferably left slack in all operative positions of the blade.

The operation of the afore-described device is evident from its structure. During the power stroke of the oar, the blade is held in the position illustrated in FIG. 1 by the pressure of the water. When the direction of oar movement is reversed for the return stroke, the lateral ribs 14 swing towards each other about the pivot pins 16, and jointly away from the central rib 15 about the hinge 13 to assume the position illustrated in FIG. 2.

When the next power stroke is started, water is urged into the opening between the lateral ribs 14 which is best seen in FIGS. 5 and 6 and which is caused by the spacing apart of the pivot pins 16 and of the associated connected end portions of the lateral ribs 14. The water caught in the folds of the upper web portion quickly expands the blade so that it is fully spread out before more than an insignificant portion of the power stroke of the oar is spent so that the oar becomes fully effective for propelling the boat practically simultaneously with the reversal of car movement.

It has been found that the particular arrangement of the elements of the invention in a blade tends to automatically correct faulty positioning of the blade by an inexperienced rower. For best performance, the oar should be positioned during the power stroke in such a manner that the face of the blade extends perpendicularly to the relative movement of water and blade. If the blade is held at an angle to the most effective position, one lateral rib will be placed forward of the other rib in the direction of oar movement. The portion of the web associated with the forward rib offers greater resistance to the water than the other portion because of the double transverse curvature of the web face. A momentum is thus set up which tends to turn the blade about the longitudinal axis of the oar and restores the proper blade position. Unless the oar is held very firmly, it will tend to twist in the hand holding it until the blade assumes the proper position.

During the return stroke, the plane of symmetry of the two halves of the web should extend in the direction of oar movement. If an inexperienced rower holds the shank portion 11 in such a manner that this is not the case, one of the ribs is positioned freely between the associated abutment edges 17 and the corresponding half of the web 18 extends in the direction of oar movement. The other lateral rib 14, however, engages the corresponding inner edge 17 of the connecting member 12. The associated web half extends obliquely into the passing stream of water and exerts a pressure on the connecting member 12 which tends to twist the oar in the operators hand until the proper position is achieved.

The oar blade of the invention may be used in any known type of oar or paddle with favorable results. It lends itself also to a method of mounting on a boat which is not available to a conventional rigid car or paddle. The oar of the invention is advantageously mounted pivotally about a horizontal or almost horizontal pivot axis extending transversely and preferably perpendicularly of the shank portion,

Such a method of mounting is illustrated in FIG. 1 which shows a pin 24 transversely passing through the shank portion 11 at right angles to the direction of oar movement so that the oar forms a two-armed lever one end portion of which is formed by the handle 25 where'- as the other end portion is constituted by the blade assembly. The pin 24 is secured in a bracket 26 which extends from a transverse boat member 27 which may be the stern or the stem. The boat is propelled by rocking the handle 25 back and forth about the pin 24. To reverse the direction of movement of the boat, the pin 24 may be removed and the oar inserted in the reversed position.

The oar or paddle blade disclosed has been found to permit rowing at high speeds with negligible drag losses during the return stroke due to the hydrodynamically correct difierent shapes of the blade during both the power and the return stroke. The oar of the invention requires very little storage space and may be further modified in well-known ways to be extremely compact where portability is desired.

The embodiment illustrated employs wood as a material of construction for the ribs and the shank and handle portions, but the invention lends itself very well to the use of light metals, for example, tubular aluminum ribs. Cotton duck, preferably rubberized, is a suitable material of construction for the web, and nylon fabric coated with plasticized polyvinyl chloride resin is preferred where maximum strength at minimum weight is necessary. Ribs of wood are preferably weighted with a piece of metal to make sure that they will not rise during the return stroke of the oar.

The hinge and pivot arrangement illustrated withstands rough handling very well. The other elements of the blade structure are as rugged as those of any rigid oar. The entire arrangement is sturdy and capable of long trouble free service.

"It should be understood, of course, that the foregoing disclosure relates to only a preferred embodiment of the invention, and that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purpose of the disclosure which do not constitute departures from the spirit and scope of the invention set forth in the appended claims.

What is claimed and desired to be protected by Letters Patent of the United States is:

1. A blade for an oar or paddle, comprising, in combination, central elongated rib means having a longitudinal axis; two elongated lateral rib means, each having a connected end portion and a free end portion; first pivot means securing said connected end portions to said central rib means in a spaced relationship with respect to said longitudinal axis for movements of said lateral rib means relative to said central rib means toward and from a first position in which said free end portions are spaced from each other and from said longitudinal axis in substantially opposite directions, second pivot means for movements of said lateral rib means about an axis transverse of said longitudinal axis between a second position in which said free end portions are located adjacent each other and spaced from said axis in substantially the same direction, and a third position in which said free end portions are located adjacent each other and adjacent said axis; pliable web means secured to said rib means and extending therebetween to form a blade face when said lateral rib means are in said first position, and to fold substantially along said axis when said lateral rib means are in said second and third positions; and stop means for preventing movement of said lateral rib means beyond said first position when said lateral rib means are moving in a direction toward said first position from one of said second and third positions.

2. A blade for an oar or paddle, comprising, in combination, central elongated rib means having a longitudinal axis; two elongated lateral rib means, each having a connected end portion and a free end portion; pivot means securing said connected end portions to said central rib means in a spaced relationship with respect to said longitudinal axis for pivotal movement of each of said lateral rib means relative to said central rib means about two axes between a first position in which said free end portions are spaced from each other and from said longitudinal axis in substantially opposite directions, a second position in which said free end portions are cated adjacent each other and spaced from said axis in substantially the same direction, and a third position in which said free end portions are located adjacent each other and adjacent said axis; each of said two axes being transverse of the longitudinal axis and the other of said two axes; pliable web means secured to said rib means and extending therebetween to form a blade face when said lateral rib means are in said first position, and to fold substantially along said axis when said lateral rib means are in said second and third positions; and stop means for preventing movement of said lateral rib means beyond said first position when said lateral rib means are moving in a direction toward said first position from one of said second and third positions.

3. A blade for an oar or paddle, comprising, in combination, a central elongated rib having a longitudinal axis; two elongated lateral ribs, each having a connected end portion and a free end portion; first means securing said connected end portions to said central rib in a spaced relationship with respect to said longitudinal axis for pivotal movements of the lateral ribs relative to the central rib toward and from a first position, in which said lateral ribs longitudinally extend in respective oblique directions from said axis, and the free end portions thereof are spaced from said axis in substantially opposite directions, second means for pivotal movements of the lateral ribs about an axis transverse of said longitudinal axis between a second position in which said lateral ribs longitudinally extend in substantially the same oblique direction from said axis, and the free end portions thereof are located adjacent each other, and a third position in which said lateral ribs longitudinally extend substantially parallel to said axis and the free end portions thereof are located adjacent each other and said axis; a pliable I sheet fastened to sid ribs and extending therebetween to form a blade face when said lateral ribs are in said first position, and to fold along said central rib when said lateral ribs are in said second and third positions; and stop means for preventing movement of said lateral ribs beyond said first position when said lateral ribs are moving in a direction toward said first position from one of said second and third positions.

4. A blade for an oar or paddle, comprising, in combination, a central elongated rib having a longitudinal axis; a connecting member hingedly secured to said central rib for pivoting movement about an axis transverse of said longitudinal axis; two elongated lateral ribs, each having a connected end portion and a free end portion; pivot means securing said connected end portions to said connecting member in a spaced relationship with respect to said longitudinal axis for pivotal movements of the lateral ribs relative to the central rib about respective axes transverse of said first and second named axes toward and from a first position in which said lateral ribs longitudinally extend in respective oblique directions from said longitudinal axis, and the free end portions thereof are spaced from said longitudinal axis in substantially opposite directions; said pivoting movement of the connecting member taking place between a second position in which said lateral ribs longitudinally extend in substantially the same oblique direction from said longitudinal axis, and the free end portions thereof are located adjacent each other, and a third position in which said lateral ribs longitudinally extend substantially parallel to said longitudinal axis and the free end portions thereof are located adjacent each other and said longitudinal axis; a pliable sheet fastened to said ribs and extending therebetween to form a blade face when said lateral ribs are in said first position, and to fold along said central rib when said lateral ribs are in said second and third positions; and stop means for preventing movement of said connecting member beyond said first position of said lateral ribs when said lateral ribs are moving in a direction toward said first position from one of said second and third positions.

A blade for an oar or paddle, comprising, in combination, central elongated n'b means having a longitudinal axis; a connecting member hingedly secured to said central rib means for pivoting movement about an axis substantially perpendicular to said longitudinal axis, said connecting member projecting from said longitudinal axis in a substantially radial direction, said direction and said longitudinal axis defining a plane of symmetry of said oar or paddle; two elongated lateral rib means, each having a connected end portion and a free end portion; pivot means offset from said longitudinal axis in said radial direction and securing said connected end portions to said connecting member for movement of said lateral rib means about two respective axes substantially parallel to said plane of symmetry for pivotal movement of said lateral rib means relative to said central rib means between a first position in which said free end portions are spaced from each other and are spaced from said plane of symmetry in substantially opposite directions, and a second position in which said free end portions are located adjacent each other and said plane of symmetry and spaced from said longitudinal axis in substantially the same direction; pliable web means secured to said rib means and extending therebetween to form a blade face when said lateral rib means are in said first position, and to fold substantially along said axis when said lateral rib means are in said second position; and stop means for preventing movement of said lateral rib means beyond said first position thereof when said lateral rib means are moving in a direction from said second toward said first position.

6. A blade for an oar or paddle, comprising, in combination, central elongated rib means having a longitudinal axis; two elongated lateral rib means, each having a connected end portion and a free end portion; first pivot means securing said connected end portions to said central rib means in a spaced relationship with respect to said longitudinal axis for movement of said lateral rib means relative to said central rib means toward and from a first position in which said free end portions are spaced from each other and from said longitudinal axis in substantially opposite directions, second pivot means for movements of said lateral rib means about an axis transverse of said longitudinal axis toward and from a second position in which said free end portions are located adjacent each other and spaced from said axis in substantially the same direction; pliable web means secured to said rib means along a longitudinal portion thereof and extending therebetween to form a blade face when said lateral rib means are in said first position, and to fold substantially along said axis when said lateral rib means are in said second position, at least said lateral ribs having longitudinally curved concave faces so as to impart a longitudinally curved concave shape to said blade face; and stop means for preventing movement of said lateral rib mean beyond said first position when said lateral rib means are moving in a direction from said second toward said first position.

7. A blade for an oar or paddle, comprising, in combination, central elongated rib means having a longitudinal axis; two elongated lateral rib means, each having a connected end portion and a free end portion; first pivot means securing said connected end portions to said central rib means in a spaced relationship with respect to said longitudinal axis for movement of said lateral rib means relative to said central rib means toward and from a first position in which said free end portions are spaced from each other and from said longitudinal axis in substantially opposite directions, second pivot means for movements of said lateral rib means about an axis transverse of said longitudinal axis toward and from a second position in which said free end portions are located adjacent each other and spaced from said axis in substantially the same direction; pliable web means secured to said rib means along a longitudinal portion thereof and extending therebetween to form a blade face when said lateral rib means are in said first position, and to fold substantially along said axis when said lateral rib means are in said second position, at least said lateral rib means having longitudinally curved concave faces so as to impart a longitudinally curved concave shape to said blade face, and said central rib means being otfset relative to said lateral rib means so as to impart a transversely curved concave shape to said blade face; and stop means for preventing movement of said lateral rib means beyond said first position when said lateral rib means are moving in a direction from said second toward said first position.

3. A blade for an oar or paddle, comprising, in combination, central elongated rib means having a longitudinal axis; two elongated lateral rib means, each having a connected end portion and a free end portion; first pivot means securing said connected end portions to said central rib means in a spaced relationship with respect to said longitudinal axis for movement of said lateral rib means relative to said central rib means toward and from a first position in which said free end portions are spaced from each other and are spaced from said longitudinal axis in substantially opposite directions, second pivot means for movements of said lateral rib means about an axis transverse of said longitudinal axis toward and from a second position in which said free end portions are located adjacent each other and spaced from said axis in substantially the same direction; and pliable web means secured to said rib means and extending therebetween to form a blade face when said lateral rib means are in said first position, and to fold substantially along said axis when said lateral rib means are in said second position.

9. A folding oar or paddle, comprising, in combination, an elongated shank portion; central elongated rib means secured to said shank portion, said shank portion and said rib means having a substantially common longitudinal axis; two elongated lateral rib means, each having a connected end portion and a free end portion; first pivot means securing said connected end portions to said central rib means in a spaced relationship with respect to said longitudinal axis for movement of said lateral rib means relative to said central rib means toward and from a first position in which said free end portions are spaced from each other and are spaced from said longitudinal axis in substantially opposite directions, second pivot means for movements of said lateral rib means about an axis transverse of said longitudinal axis toward and from a second position in which said free end portions are located adjacent each other and spaced from said axis in substantially the same direction; pliable web means secured to said rib means and extending therebetween to form a blade face when said lateral rib means are in said first position, and to fold substantially along said axis when said lateral rib means are in said second position; and stop means for preventing movement of said lateral rib means beyond said first position thereof when said lateral rib means are moving in a direction from said second toward said first position.

10. In the blade according to claim 1, said transverse axis being substantially perpendicular to the longitudinal axis.

ll. In the blade according to claim 4, said transverse axis being substantially perpendicular to said first and second named axes.

12. In the blade according to claim 4, said connecting member projecting laterally from said central rib on one side thereof, said pivot means being provided on the connecting member, and said respective axes being parallel.

13. In the blade according to claim 1, one portion of said web means extending between the free end portions of the lateral rib means, and another portion of said web means extending between the connected end portions of the lateral rib means, said one web means portion being taut, and said other web means portion being slack, when said lateral rib means are in said first position.

References Cited in the file of this patent UNITED STATES PATENTS 359,374 Wright Mar. 15, 1887 10 Smith Oct. 18, 1910 Beebe Sept. 29, 1925 Znkal Nov. 23, 1926 Swenson June 10, 1952 Trell Mar. 23, 1954 Wagner Feb. 7, 1956 Crum Nov. 27, 1956 FOREIGN PATENTS Germany Aug. 19, 1924

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