US2120780A - Fan - Google Patents

Description

June 14, 1938. w, A EI E 2,120,780

FAN

Filed Jan. 20, 1934 gwwmtoz Patented June 14, 1938 PATENT OFFICE FAN Walter A. Geise, Flint, Mich., assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Application January 20, 1934, Serial No. 707,493

3 Claims.

I have found that the noise which is produced as the result of the operation of the propelling engine of an automotive vehicle may be corisiderably reduced or, at least, rendered much less apparent or objectionable by so constructing and/or arranging the blades of the engine cooling fan that one of them imparts to the air an impulse whose characteristics diiler from that imparted to the air by another blade or, to be more specific, by making the angular pitch and/or the size and/or the shape of one of the blades different from that of another blade.

My invention may be embodied in multi-blade fans which have even or uneven numbers of blades; and in either type of fan, the angular pitch and/or the size and/or the shape of one blade may be different from the angularpitch and/or the size and/or the shape of the other blade or blades or the angular pitch and/or the size and/or the shape of one blade may be different from the angular pitch and/or the size and/or the shape of another blade or blades but the same as the angular pitch and/or the size and/or the shape of still another blade or blades.

For a better understandingmf the nature and.

objects of the present invention, reference is made to the following specification in which there are described the preferred embodiments of my invention which are illustrated in the accompanying drawing, in which: 1

Figure 1 is a fragmentary side elevation of the front end of an automotivevehicle in which is installed an engine cooling fan in which isem bodied my invention.

Figure 2 is a front elevation of the engine cool ing fan which is shown in Figure 1.

In Figure 3, A-A, B-B, C-C andD-D indicate, respectively, sections on the lines A-A,

B-"'B, C-C and DD of Figure 2.

Figures 4 and 5 are, respectively, a side ale-'- vation and a front elevation of another engine cooling fan in which my invention is embodied.

In the drawing, the reference character 9 indigates the water cooling radiator of an automotive vehicle and the reference character lo the propelling engine thereof. To draw cooling air through the radiator and force it over the engine, there is provided a fan H which is arranged to be driven through any ordinary or suitable mechanism by the engine It.

'I'he'fan H, which is shown in Figures 1, 2 an 3, consists of a hub I2 on which there are mounted equi-angularly around the axis of rotation of the fan four propeller or screw typefan blades l3, l4, l5 and Hi which may be of the same size and shape or of different sizes and/or shapes but, as Figure 3 clearly shows, have different angular pitches. The fan l'l, which is shown in Figures 4 and 5, consists of a hub it to which there is secured a spider I9 on which 5 there are mounted equi-angularly around the axis of rotation of the fan four propeller or screw type fan blades 20, 2|, 22 and 23 which may have the same or different angular pitches but are,- as Figure 5 clearly shows, of difierent sizes and/or shapes.

What angular pitches and/or sizes and/or shapes the several blades of a fan in which my invention is embodied should be given to produce a fan which gives the most highly satisiactory results may be determined by experiment. However, it should here be noted that the fan which will operate most satisfactorily in one installation is not necessarily the fan which will operate most satisfactorily in another installation and, consequently, that since, practically speaking, what is to be considered is not how quietly the fan operates when divorced from its intended surroundings, but how quietly the installation as a whole is when the fan is operat- 5 ing, the experiments should be conducted with :the fan incorporated in the installation in which it is intended to be used and the most highly satisfactory results should be considered to have been attained when the installation as a whole is most quiet when the fan is operating.

To eliminate the possibility of a misunderstanding of what has been said in the next preceding paragraph, I should, perhaps, point out that it is not necessary by experiment to design a fan for each example of an installation, since when a fan suitable for a particular example ofan installation has been produced, similar fans may, without'furthe'r experimentation, be satisfactorily 40 employed in all examples of that installation.

Although I have shown and described as preferred embodiments of my invention four-blade fans, it will be understood that the principles underlying my invention may be incorporated in 5 fans which have a greater number of blades as well as in two-blade and three-blade fans.

I claim:

1. A screw propeller which consists of more than three substantially identical blades of which 0 each diflers in pitch and is spaced angularly around the axis of rotation of the propeller from each of the others, so disposed that they rotate in substantially the same plane and are arranged around the axis of rotation of the proscrew propeller which consists of a plurality of substantially identical blades, so disposed that they rotate in a single plane positioned between said radiator and engine whereby air is drawn through the former and propelled over the latter, each of the blades dlflering in angular pitch from each of the others and spaced angularly around the axis of rotation of the propeller in the numerical order of their pitches, so that in the operation of the propeller the noise produced as the result of the operation of the engine is minimized. v

WALTER A. GEISE.

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