US2270615A - Propeller - Google Patents

Description

' Jan. 20, 1942.

E. E. BALDWIN PROPELLER Filed Oct. 11, 1940 Patented Jan. 20, 1942 UNlTED STATES PATENT OFFICE PROPELLER Edward E.- Baldwin, New York, N. Y. Application October 11,1940, Serial No. 366,823 1 3 Claims.

working surface, and these webs may be con-- nected by a continuous concentric ring which provides a balanced bearing surface in the fluid in which the propeller is operating.

Propellers have been provided in tubes or with concentric bands at the tips of the blades, but these have not been successful because they hold the fluid at both sides of the blade, whereas it is desirable to permit the fluid to escape on the vacuum side and hold it on the power or thrust side.

The object of this invention is therefore to shape an eccentric band at the tips of propeller blades so that there is substantially no obstruction on the vacuum surfaces of the blades, whereas the power or thrust surfaces have means for holding the fluid to prevent its slipping off the ends of the blades.

Another object is to provide means on the power surfaces of propeller blades for preventing radial slip of fluids in which the propeller is working.

A further object is to provide a propeller having a concentric ring forming a bearing surface in a fluid which does not prevent the free escape of fluids from the vacuum surface of the blade.

And a still further object is to provide a propeller having means for substantially eliminating slip and also for forming a bearing in the fluid in which it is operating, which is of a simple and economical construction.

Other features and advantages of the invention will appear from the following description, taken in connection with the drawing, wherein:

Figure 1 is a view showing the forward side of the propeller.

Figure 2 is a view showing a side elevation of the propeller shown in Figure 1.

Figure 3 is a view looking toward the opposite or rear side of the propeller.

Figure 4 is a detail showing a cross section through one of the propeller blades looking toward the ring at the periphery thereof.

alternate design in which the ring at the tips of the blades is broken and webs are provided on the blades.

Figure 6 is a view showing a side elevation of the propeller shown in Figure 5.

Figure 7 is a detail showing the suction of fluids into the propeller at one side and the path of the discharge of the fluids at the opposite side.

In the drawing the propeller is shown as it may be made, wherein numeral I indicates the blades,

' numeral 2 the hub, and numeral 3 the concentric ring.

The ring 3 preferably extends continuously around the propeller connecting the ends of the blades substantially at the points of the greatest width thereof, or with the tips of the blades omitted, and this ring is provided with recesses 4, one edge of which registers with the forward, leading or vacuum surface 5, of each blade, whereas the opposite end of the recess tapers forward on a line 6 toward a point 1 which corresponds with the leading edge of the following blade of the propeller. This forms an enclosed pocket 8 on the trailing surface which prevents the free passage of fluids off the ends of the blades and thereby harnesses the power or force lost 01f the end of the blades, which is commonly known as slip. It will be understood that the shape of the pocket or concentric ring 3 may be changed, or the pocket may be formed in any manner.

The propeller may also be made as shown in Figures 5 and 6 in which webs 9 and Ill are provided on the back of the blades and although two webs are shown, it will be understood that any number of webs may be used and these may be of any shape or design. These webs will also hold the fluid and cause it to discharge straight outward from various points along the blades,

providing a relatively compact stream of liquid or air behind the propeller.

It will be understood that other changes may be made in the construction without departing from the spirit of the invention. One of which changes may be in the use of the ring with a propeller for air instead of the water wheel as illustrated, another may be in the use of the device with a propeller having any number of blades, and still another may be in the use of a concentric ring of any other type or design in which the ends of the forward surface of the blades are open and the working surface closed.

The construction will be readily understood from the foregoing description. In use the pro- Figure 5 is a view showing a propeller of an peller may be provided as shown and described,

and it will be noted that as it revolves the concentric band will form a bearing in the fluid in which it is operating, and fluids will be drawn into the forward side of the wheel as illustrated in Figure 7, and discharged from the rear or from the working surfaces of the blades substantially outward in a straight line, instead of merely churning the water, and at the same time the vacuum surfaces are free and unobstructed permitting free passage of these surfaces of the blades.

Having thus fully described the invention what I claim as new and desire to secure by Letters Patent, is: a

1. A propeller having a hub with blades extending therefrom, and a relatively narrow ringconcentric with the hub and attached to the outer ends of the blades with the rear edge ofv the ring flush with the trailing edges of the blades, and v with the width of the ring extended to the leading edges of the blades on the pressure sides of the blades forming pockets on the said pressure sides for holding fluids preventing the free escape of fluids from the ends of the blades on the pressure surfaces thereof, and characterized in that the width of the ring is materially reduced behind and between the blades providing free and unobstructed escape of fluids from the suction surfaces of the blades.

2. A propeller as described in claim 1, in which the width of the blades increases toward the V outer ends of the blades.

3. A propeller as described in claim 1, in which the width of the ring at any point does not exceedthedistance from the leading edges of the blades to a plane passing through the trailing edges of the blades.

' EDWARD E. BALDWIN.

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