US2098640A - Fan construction - Google Patents

Description

Nov. 9, 1937. B. B. CARY FAN CONSTRUCTION Filed May 15, 1936 Beecher- 5. Cau L 9 51m] @5 a Patented Nov. 9, 1937 UNITED STATES FAN CONSTRUCTION Beecher B. Cary, Jackson, Mich., assignor to Hayes Industries, Inc., Jackson, Mich., a corporation of Michigan Application May 15, 1936, Serial No. 79,949

1 Claim.

The present invention relates to fans, being particularly concerned with multiblade fans of the propeller or screw type used in automobiles to draw the cooling air through the radiator.

My invention is considered to be an improvement overthe fan construction disclosed in U. S.

Patent No. 1,983,606, granted December 11, 1934.

Through the principle as disclosed in the aforesaid patent of having the angle between one blade and the following blade difierent from that between the two adjacent following blades, objectionable fan noises heretofore experienced have been materially eliminated. Tests have shown, however, that a fan embodying such a principle having an equal number of blades with diametrically opposite angles between adjacent blades equal is less effective in reducing noises than a fan in which all the angles between am'acent blades are diiferent. From the commercial point of view, the construction with an equal number of blades and equal diametrically opposed angles between adjacent blades has the advantage of being in static balance. The other type of construction as disclosed in the aforesaid patent required special counterbalances or blades of different weight which until the present development prevented its commercial use although having great efficiency in respect to noise elimination.

According to the present invention, a fan is provided having an unequal number of blades with the angles between each adjacent pair of blades different from that of any other adjacent pair of blades which is made up from two or more separate statically balanced fan units. Preferably two units are employed of three blade and two blade construction, all equally spaced and of the same weight, although units of three blades and fourblades can be associated in the same manner, and so on. Thus, an object of the present invention is to provide a fan of the aforesaid type having an unequal number of equal weight blades, all unequally spaced yet so associated as .to be in static balance.

Another object is to provide a fan of the aforesaid type made up of two or more separate balanced units having an unequal number of blades and unequally spaced with the blades of each unit equally spaced when separately considered.

These and other objects and advantages of the invention will appear from the following detailed description. The invention is defined in the engine in an automotive vehicle showing my improved fan when it is installed for rotation,

Fig.2 is an exploded perspective view showing the two separate fan units slightly separated for the sake of clarity, and

Fig. 3 is a front elevational view showing the two units in imposed relation to form a unitary fan structure.

Referring to the drawing the fan construction It shown in Fig. 1 as positioned between the radiator I2 and engine 14 of automotive vehicle is supported upon the hub l 6 for rotation at rates directly proportional to the speed of the engine H. The fan I is preferably made up from two separate units I8 and 20 as shown in Fig. 2 which are separately constructed and statically balanced prior to being assembled into the unitary structure shown in Fig. 3. Each of the units I8 and 20 comprises a sheet metal spider 22 and 24 having radial arms 26 and 28, respectively, which are equally spaced in each unit. The blades 30, 32 and 34 of equal weight are supported from the arms 26 of the spider 22 while blades 36 and 38 of equal weight are similarly supported in the arms 28 of the spider 24. In production all of the blades will be identical in construction and of equal weight and as the spiders 22 and 24 all have their center of mass at the axis of rotation and the blades are supported on the arms of the spiders at equal distance from the center of I rotation it will be readily appreciated that the two blade or even number and three blade or odd number of fan units may be readily produced in substantially static balance. Thus, as both the units to be associated as shown in Fig. 3 are in substantial static balance the resulting unitary structure obtained with the spiders l2 and I4 in concentric imposed relation will likewise be in Static balance regardless of the relative angular positioning of the associated units.

Without limiting the invention to the specific angles between the adjacent blades of the unitary fan structure, as shown in Fig. 3, it is enough to state that the separate units are so arranged that all angles between any pair of adjacent blades are difierent. In commercial practice a very satisfactory fan has been provided by spacing the trailing edges of the blades 34 and 36 42 apart, the trailing edges of the blades 30 and 36 77 apart, the trailing edges of the blades 38 and 30 102 apart, and the trailing edges of the blades 32 and 38 17 apart.

The spiders 22 and 24 may be spot welded together with the fan units in the relative position as shown in Fig. 3 and the fan structure concentrically supported upon the hub l6 by suitable studs extending through the bolt holes ill. The stock from which the spiders 22 and 24 are formed is preferably of such a gauge that when one is 5 imposed upon the other the blades of the unitary Ian structure are substantially coplanarily disposed around the axis of rotation. The advantage of being able to stamp all the blades from the same gauge material and of substantially 10 identical shape and weight and to similarly fabricate the spiders 22 and 24 and then to merely assemble two or more fan units to give a balanced i'an structure to provide a fan having the characteristics desired will be readily appreciated.

15 Having thus described my invention what I desire to protect by Letters Patent and claim is:

A rotary fan for automobiles and the like comprising a pair of fan units each having individual central spider structures, one of said units having an odd number of equally spaced blades, the other of said units having an even number of equally spaced blades, said spider structures being juxtaposed'and held in relatively fixed relation, all of said blades being substantially coplanarily disposed around the axis of rotation and so arranged that the angles between adjacent blades are all diiferent, said units being individually and collectively in static balance.

BEECHER B. CARY.

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