US3609060A

US3609060A - Marine propeller

Info

Publication number: US3609060A
Application number: US841345A
Authority: US
Inventors: Alberto Angel
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-07-14
Filing date: 1969-07-14
Publication date: 1971-09-28
Anticipated expiration: 1988-09-28

Abstract

A hub having an enlarged midsection and tapered forward and rearward portions is adapted to be attached to a propeller drive shaft. A plurality of outwardly extending arm members support a plurality of curved blades in a spaced-apart manner from the hub. The blades are positioned for squeezing water inwardly toward the rotational axis of the propeller during rotation of the propeller for increasing the water pressure adjacent the rearward portion of the hub for producing a desired forward thrust for the propeller.

Description

United States Patent [72] Inventor Alberto Angel 8606 Morley, Houston, Tex. 77017 [21] App1.No. 841,345 [22] Filed July 14, 1969 [45] Patented Sept. 28, 1971 [541 MARINE PROPELLER 8 Claims, 4 Drawing Figs.

[52] U.S.C1 416/179, 416/236, 416/242 [51] Int. Cl B63h1/16 [50] Field oisearch 416/179,

[56] References Cited UNITED STATES PATENTS 3,504,990 4/1970 Sugden 416/211 X FOREIGN PATENTS 15,012 8/1911 Denmark 416/180 99,797 9/1897 Germany..... 416/210 5,294 1913 Great Britain 416/210 Primary Examiner-Everette A. Powell, Jr. AttorneysRichard E. Bee, Giles C. Clegg, Jr. and Jack A.

Kanz

MARINE PROPELLER BACKGROUND OF THE INVENTION This invention relates to marine propellers for propelling boats, ships and other types of marine vessels through water.

As is known, present day marine propellers are not lpercent efficient. All of the power applied to the propeller drive shaft is not converted into forward movement of the boat.

Various advantages could be realized through the use of a more etiicient propeller. The rate of fuel consumption for a given operation could be reduced. The speed of the vessel could be increased. The overall diameter of the propeller could be reduced. A motor having a lower maximum power rating could be used. Or a combination of these advantages could be realized.

As is further known, every present day propeller has a definite upper limit as to the rate at which it can be rotated. If this limit is exceeded, then cavitation eflects occur. Such effects can become sufficiently violent to cause damage to the propeller and the mechanisms driving same.

A marine propeller capable of operating at higher revolution rates than present day propellers would offer various advantages. For the case of larger oceangoing type boats and ships, for example, it would enable a more direct connection of the propeller to the high speed turbines commonly used, thus providing a further improvement in overall efiiciency.

SUMMARY OF THE INVENTIOn It is an object of the invention, therefore, to provide a new and improved marine propeller of increased eficiency.

It is another object of the invention to provide a new and improved marine propeller capable of operating at a higher number of revolutions per minute with reduced vibration effects.

In accordance with the invention, a marine propeller comprises hub means having an enlarged midsection and tampered forward and rearward portions. The propeller also includes means for coupling the hub means to the marine vessel to be propelled so that water may freely flow over the hub means from the forward end to the rearward end thereof. The propeller further includes blade means spaced laterally of the rearward portion of the hub means and means for rotating the blade means around an axis coaxial with the longitudinal axis of the hub means. The blade means are shaped to cause an inward squeezing of the water as it flows past the rearward portion of the hub means for increasing the water pressure on the rearward portion of the hub means.

For a better understanding of the present invention, together with other and further objects and features thereof, reference is bad to the following description taken in connection with the accompanying drawing, the scope of the invention being pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWING Referring to the drawing:

FIG. 1 is a perspective view of a first embodiment of a marine propeller constructed in accordance with the present invention;

FIG. 2 is a rear elevational view of the FIG. 1 propeller;

FIG. is a cross-sectional plan view taken along section line 3-3 of FIG. 2; and

FIG. 4 is a rear elevational view of a second embodiment of a marine propeller constructed in accordance with the present invention.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS Referring to FIGS. 1-3, there are shown various views of a first embodiment of a marine propeller constructed in accordance with the present invention. This embodiment includes a hub adapted to be attached to a propeller drive shaft 11, which drive shaft 11 is connected to an appropriate motor or turbine unit (not shown) located aboard the ship to be propelled. Shaft 11 rotates in the counterclockwise direction as viewed from the hub end in FIG. 1. Hub 10 is provided with an appropriate interior receptacle or socket for receiving the end of the shaft 11. Appropriate elements such as keys, keyways, retaining pins and the like are provided for fastening the hub 10 to the shaft 11 and for transferring the rotary motion of shafl 11 to the hub 10. As best seen in FIG. 3, the hub 10 includes an enlarged midsection 12 and tapered forward and

rearward portions

13 and 14. Such forward and

rearward portions

13 and 14 are of generally conical shape with the axes of the cones being in line with one another and with the longitudinal or rotational axis of the propeller shaft 1 1. These cones are of different altitudes or axial dimensions with the altitude of the forward cone 13 being the greater.

Disposed about the hub 10 are a plurality of

curved blades

15, 16, 17 and 18 which, as indicated in FIG. 2, are spaced apart from the hub 10 and encircle the hub 10 in an overlapping manner. Each of the blades 15-18 is in the form of a curved plate. For the present example, the curvature of each blade as viewed in the edgewise manner of FIG. 2 is intended to correspond to a potion of a spiral type curve. More particularly, it is intended to correspond to a portion of an involute of a circle. As indicated in FIG. 3, the blades 15-18 encircle the rearward portion 14 of the hub 10. The concave sides 15a-18a of the blades 15-18 face the hub 10 and the blades are positioned so that their leading rotational edges 15b-18b are at a greater radial distance from the longitudinal center axis of the hub 10 than are their trailing rotational edges -180. As indicated in FIG. 2, the thickness of each blade is greatest at its trailing rotational edge and decreases to a relatively thin knife edge like dimension at its leading rotational edge.

The curved blades 15-18 are supported from the hub 10 by means of support means represented in the present embodiment by a plurality of

arm members

21, 22, 23 and 24 which extend outward from the hub 10. These arm members 21-24 are attached to the hub 10 immediately ahead of the maximum diameter midsection line 12. As indicated in FIG. 3, these arm members 21-24 are attached to the forward portions of the blades 15-18. Each of the arm members 21-24 has attached thereto at an intermediate point the trailing rotational edge of one of the blades and at a greater radial distance a more leading rotational portion of a second of the blades, such leading portion being near the leading rotational edge of such second blade. As indicated in FIG. 1 for the case of the blade 16, a recess 16d is formed in the blade 16 near the trailing rotational edge for enabling passage of the arm member 21 to the more distant portion of the overlapping blade 15. Similar recesses are provided in the other

curved blades

15, 17 and 18.

As indicated in FIG. 3 for the arm member 24, the arm members 21-24 are provided with a tapered cross-sectional shape and are cocked at an angle so that one of the tapered edges is nearer the front of the hub 10 than is the other. This angle is such that when the propeller rotates the arm members 21-24 also function like small propeller blades and, as such, serve to urge movement of the water in the rearward direction The main function of the arm members 21-24 is, however, to support the primary blades 15-18, the propeller action provided by such arm members 21-24 being more in the nature of making the most of structures that are needed for other purposes.

In operation, the curved blades 15-18 function to urge or squeeze the water inwardly against the tapered rearward portion 14 of the hub 10 during rotation of such blades 15-18. The sloping shape of this rearward portion 14 serves to deflect the inwardly directed hydraulic flow in a rearwardly direction and thus out the back end of the propeller assembly. The tapered shape of the forward portion 13 of the hub 10 functions to direct the water entering the propeller assembly from the forward direction in an outwardly direction toward the curved blades 15-18, from whence it is squeezed back in toward the rearward portion 14 of the hub 10. Thus, the shape of both the forward portion 13 and the rearward portion 14 are important in organizing the flow of the water through the propeller assembly.

While it is convenient to think in terms of movement or flow of the water, this tends to overlook the primary significance of the present invention. The more significant aspect of the matter is that the squeezing of the water inwardly causes a very substantial increase in the water pressure in the center portion of the region which is bounded by the curved blades 15-18. As is known from established hydraulic principles, this pressure is transmitted equally in all directions. As a consequence, it reacts against the rearward portion 14 of the hub and the rearward sides of the arm members 21-24 to produce the desired forward thrust on the propeller shaft 11 for propelling the boat or ship through the water.

A conventional propeller operates more in the manner of a screw. The blades of the convention propeller engage the water and produce a direct thrust thereon which pushes the water in the rearward direction. With the present propeller, on the other hand, the primary blades 15-18 are not engaged in such a rearward pushing of the water. instead, they function to squeeze the water to increase the water pressure on the back side of the propeller hub. As a consequence, the buildup of a vacuum condition on the forward side of the propeller assembly does not occur nearly so readily nor to the same extent as with a conventional propeller. Thus, the present propeller may operate at a considerably higher number of revolutions per minute before the cavitation point is reached.

Referring to FIG. 4, there is shown a rear elevational view of a second embodiment of a propeller constructed in accordance with the present invention. The propeller that FIG. 4 includes six curved blades 30 which are mounted in a spacedapart manner about a central hub 31 by means of six arm members 32. The hub 31 is provided with tapered forward and rearward portions in the same manner as for the hub 10 of the first embodiment. The arm members 32 of FIG. 4 extend radially only to the trailing rotational edges of diflerent ones of the curved blade 30. Additional support for the blades 30 is provided by a circular support ring 33 which is attached to the forward portions of the blades 30 at a greater radial distance than the extremities of the arm members 32. As in the earlier embodiment, the blades 30 function to increase the water pressure adjacent the sloping rearward portion of the hub 31 for purposes of producing the desired forward thrust on the propeller shaft.

Propellers constructed in accordance with the present invention may be used with either inboard or outboard type motors. For larger size boats or ships, two or more such propellers may be used on a given boat or ship. Also, the pressure increasing curved blades of the present invention may, if desired, be used in combination with conventional propeller blades.

A propeller constructed in accordance with the present invention can very readily provide a 10 percent improvement in efficiency as compared with a conventional propeller of the same overall diameter. With the exercise of proper care, the improvement can be more on the order of percent.

While there has been described what are at present considered to be preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore, intended to cover all such changes and modifications as fall within the true spirit and scope of the invention. What is claimed is: l. A marine propeller comprising: hub means having an enlarged midsection and tapered forward and rearward portions; means for coupling the hub means to the marine vessel to be propelled so that water may freely flow over the hub means from the forward end to the rearward end thereof; blade means spaced laterally of the rearward portion of the hub means; means for rotating the blade means around an axis coaxial with the longitudinal axis of the hub means; and the blade means being shaped to cause an inward squeezing of the water as it flows past the rearward portion of the hub means for increasing the water pressure on the rearward portion of the hub means.

2. A marine propeller comprising:

a hub having an enlarged midsection and tapered forward and rearward portions;

a propeller shaft for coupling the hub to the marine vemel to be propelled and for spacing the hub apart from the hull of the vessel so that water may freely flow over the hub from the forward end to the rearward end thereof;

a plurality of curved blades;

and support means for spacing the blades laterally of the rearward portion of the hub with the concave sides of the blades facing the hub and positioned for squeezing water inwardly toward the rearward portion of the hub during rotation of the propeller.

3. A marine propeller in accordance with claim 2 wherein the shape of the hub corresponds to a pair of conical forms having a common base and pointing in opposite directions.

4. A marine propeller in accordance with claim 2 wherein the curvature of each blade corresponds to a portion of a spiral.

5. A marine propeller in accordance with claim 2 wherein the support means comprises a plurality of angularly spaced arm members which extend outwardly from the hub.

6. A marine propeller in accordance with clam 5 wherein the arm members are attached to forward portions of the curved blades.

7. A marine propeller in accordance with claim 6 wherein the arm members are cocked at an angle so as to urge movement of water in the rearward direction.

8. A marine propeller in accordance with claim 2 wherein:

the shape of the hub corresponds to a pair of conical forms having a common base and pointing in opposite directions;

each blade is in the form of a curved plate;

the blades are positioned to encircle the rearward portion of the hub in an overlapping manner;

and the support means comprise a plurality of angularly spaced arm members which extend outwardly from the hub and are attached to forward portions of the blades.

Claims

1. A marine propeller comprising: hub means having an enlarged midsection and tapered forward and rearward portions; means for coupling the hub means to the marine vessel to be propelled so that water may freely flow over the hub means from the forward end to the rearward end thereof; blade means spaced laterally of the rearward portion of the hub means; means for rotating the blade means around an axis coaxial with the longitudinal axis of the hub means; and the blade means being shaped to cause an inward squeezing of the water as it flows past the rearward portion of the hub means for increasing the water pressure on the rearward portion of the hub means.

2. A marine propeller comprising: a hub having an enlarged midsection and tapered forward and rearward portions; a propeller shaft for coupling the hub to the marine vessel to be propelled and for spacing the hub apart from the hull of the vessel so that water may freely flow over the hub from the forward end to the rearward end thereof; a plurality of curved blades; and support means for spacing the blades laterally of the rearward portion of the hub with the concave sides of the blades facing the hub and positioned for squeezing water inwardly toward the rearward portion of the hub during rotation of the propeller.

8. A marine propeller in accordance with claim 2 wherein: the shape of the hub corresponds to a pair of conical forms having a common base and pointing in opposite directions; each blade is in the form of a curved plate; the blades are positioned to encircle the rearward portion of the hub in an overlapping manner; and the support means comprises a plurality of angularly spaced arm members which extend outwardly from the hub and are attached to forward portions of the blades.