US578860A - Organ-fan and case - Google Patents

Description

(No Model.) Y 2 Shegts-'Sheet 1.

Mn 4 ORGAN FAN AND CASE.

No. 578,860. Patented Mar. 16, 1897.

UNITED STATES PATENT OFFICE.

MELVILLE CLARK, OF CHICAGO, ILLINOIS.

oRcAN-FAN AND CASE.

SPECIFICATION forming part of Letters Patent No. 578,860, dated March 16, 1897.

Application filed September 9, 1895. Serial No. 561,879. (No model.)

To all whom it may concern,.-

Be it known that I, MELVILLE CLARK, a citizen of the United States, residing at Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Organ-Fans and Cases, which are fully set forth in the following specification, reference being had to the accompanying drawings, forming a part thereof.

In the drawings, Figure 1 is a front elevation of my improved organ-fan, showing also in general outline an electric motor for operating it and by which it is supported. Fig. 2 is a section at the line 2 2 on Fig. l, showing a fan in side elevation. Fig. 3 is a horizontal section of the fan at the line 3 Bon Fig. 1, showing the motor in general outline' in plan partly broken away. Fig. 4 is a side elevation of the fan-wheel. Fig. 5 is a detail elevation giving an inner View of the outer half of the fan-case partly broken away.

The purpose of the present invention is to provide a fan for organs which shall operate noiselessly. The difficulties to be overcome in order to accomplish this result are due to three principal causes.

First. The rapid motion of the fan tends to produce a shaking or trembling of the structure,because it is exceedingly difi cult to make the fan absolutely balanced, and the high rate of speed at which it runs, varying from two thousand to six thousand revolutions per minute, makes the slightest irregularity productive of very perceptible shake.

Second. The vanes of the fan tend to buffet the air, and even revolving in the open air a' musical tone whose pitch depends upon the number of vanes and the rate of rotationthat is to say, upon the frequency with which the vanes pass any given pointcan always be observed in any fans heretofore made. This is probably due to the fact that even when standing in the open air without a case the condition of the air surrounding the fan is not absolutely uniform, air-currents tending to vary the density of the air at different points in the circumference of the fan, and the passage of the vane past the points of variation or across a current operates to produce a vibration whose frequency depends upon the frequency of su ch passage and yields the musical tone observable. Whatever the cause may be, however, the fact is as stated.

Third. When a fan is inclosed in a case, as it must be in order to serve the purpose of an organ-fan, to wit, to produce the air-current necessary for operating the reeds or pipes of the organ, the rotation of the vanes past the discharge-mouth of the fan yields a distinct and often strong musical tone for the very evident reason that a distinct impulse to the air is given as-each vane passes the mouth or any point at which the restriction may be located, as where the fan-vanes pass near to the wall of the case at the junction of the discharge-,mouth therewith.

A fourth cause operates to some extent in all fans heretofore applied to such purposeviz., that the fan-shaft when it obtains bearingsin the fan-case tends to communicate to the case any vibration which the fan itself may experience from the contact of its vanes with the air as they revolve.

Another point to be observed in order to promote noiselessness when the fan is to be directly associated with the motor which operates it is that any vibration due to the action of the motor itself should not be communicated to the fan-case, which by reason of its form is liable to operate as a soundingboard or magniiier of any sound which might be caused by such vibration originating in the motor frame or bearings.4

In my improved fan herein described I overcome all these difficulties and produce a noiseless fan; that is to say, a fan devoid of musical tone and one from which neither vibration nor shaking or trembling motion is communicated to its supports. I overcome the danger of shaking movement being communicated from the fan-wheel to the fan-case and supports by making the fan-wheel itself Very light, forming it preferably of wood or molded paper and mounting it directly on the shaft of the electric motor, which with its framework is very heavy in comparison with the fan-wheel, and by mounting the fan-case also directly on `the motor-frame, so that it is entirely independent of the fan, except that they both obtain support ultimately on the roo motor-frame, and by providing the motor with rubber feet constituting its sole immediate support. In order to easily sustain the fan-case on the motor without giving the case any other support `than its connection with the motoreframe, I make the fan-case very light by the mode of construction hereinafter described. I overcome the second difficulty by inclosin g the fan-van es between two disks, beyond whose edges the vanes do not project at all, and setting the vanes with their outer edges at the periphery of the wheel oblique to the plane of rotation, the angle being not far from forty-five degrees, so that the vanes do not buffet the air as the fan revolves, and so do not produce pulsations, the air being cut bythe vanes as they revolve somewhat, as by a Wedge @leaving it. I overcome the third difficulty by making the fan-case of fabric impervious to air, but practically devoid of resonant quality. I use for this purpose any of the familiar makes and qualities of waterproof cloth, the variety known as mackintosh cloth being entirely suitable. Such cloth, cut into pieces suitably lshaped to form,

when .placed edge to edge and curved so that their edges Will meet, a case of the desired circular form, I secure to the framework of wooden ribs, as hereinafter more particularly explained. Vhatever vibration such a fancase can have is absorbed by the rubber feet of the motor and prevented from producing an audible tone. I Will now describe the structure in detail.

A represents the electric motor, of which A is the spindle or shaft.

B B is the fan-case, which is secured by arms C C to the motor-frame and has no other support. The arms C C are made to extend one at each side of the motor-frame and are secured to the latter by bolts c c through slots or elongated holes C C/ in the arms C C. This construction provides foradjustment of the fancase toward and from the motorframe, as may be necessary, to locate it properly with respect to the fan D, which is fixed upon the end of the shaft A within the case B. The case B B is made in two parts B and B', the part B, I will call the back and the part B the front half of the case. The back B is open at the center and around the shaft A', so that the latter has no bearing in or contact with the case. This opening may without detriment to the action of the fan be as large as the mouth or front opening of the case. The front case of the half B has at its center the mouth B10, surrounded by the flange B11, to whichthe intake-pipe B12is connected. Each half of the fan-case comprises a frame consisting of light wooden ribs t t, &c., arranged radially and joined rigidly to the annulus b', encircling the central opening, and to the flange b2 at the outer periphery or equatorial planeof the case. To this frame and Within it I secure air-proof fabric cut in sectoral pieces B3 B3, 85e., adapted to extend from rib to rib of the frame, their radial edges being suitably curved,so that when the pieces are laid to the curvature of the ribs said radial edges b3 shall abut accurately as they lie adjacent to each other on the inner surface of the ribs, respectively. The pieces B30 and B31, which form the discharge-mouth of the fan, are specially shaped as necessary to conform to the cylindrical curvature of that mouth, and also to the curvature of the fancase back of the mouth. The piece B31 is necessarily slightly crimped at the curve B31, but not sufficiently to interfere with the sul stantially accurate formation of the case in this manner. I prefer to make the rib 1330 substantially in the form shown, so that it extends radially with respect to the fan-case until it reaches the greatest diameter of the cylindrical mouthpiece and then turns to a direction transverse to the cylindrical mouthpiece and extends to the flange b2. The fabric cut as described is glued or secured in some equivalent manner to the inner surface of the ribs Z9 and annulus b', the edges abutting accurately, as stated, and it is folded over the inner corner of flange b2 and glued onto its face. The two halves of the fancase thus formed are secured together by screws taking through their flanges b2, respectively, as seen in Fig. 3. The two halves of the case are precisely alike, and their several parts are enumerated, therefore, by the same letters, except that the front half hasits annulus b extended in the flange B11, as described.

I will now describe the fan-wheel. This fan-wheel is made of wood, hard rubber, celluloid, or any material which can be constructed so as to avoid projections, either of screws, bolt-heads, ribs, or beads, from any part of its rotating surface transversely to the path of rotation. Then made of wood, it will be glued up in a manner which needs no explanation. It comprises the back D, the annular front disk D2, and the vanes D3. The back D is a disk without opening, which may be liollowed at the rear, as indicated by the dotted line d', and which at the forward side is curved convexly. The annulus D2is outwardly convex and of substantially uniform thickness. Its central opening is a little greater than the eye or central opening B10 of the fan-case. The ribs D3, extending between the back D and the annular front D2 of the fan-wheel, are distinguished by two characteristics-first and chiefly, that at their outer edges they stand at an oblique angle to the plane of rotation, their angle to the back D orto the plane of its rotation at the periphery of the disk and outer edge of the vane being approximately forty-five degrees. The vanes are also curved so that they are convex toward a radial plane through their inner ends or edges. This gives them the appearance of being curved transversely; that 1s, extending in curved direction across the IOO IIO

space between the front and back as they appear in direct edge view.

By shaping the vanes of the fan as described, and particularly so that at their outer ends their edges are quite oblique to the plane of rotation, I prevent the bufteting of the air by the vanes as the Wheel revolves, because they as it were wedge their way through the air as they advance in the oircular path of rotation of the Wheel. I find by experiment that it is possible to totally destroy the tone which the vanes are liable to produce when the wheel has a high rotary speed merely by this expedient of twisting the vanes so that their edges at the periphery of the wheel stand oblique, as described.

The entire fan and case being made very light by the structure described maybe safely mounted on the motor, which is relatively heavy, so as to overhang from the motorcase, as illustrated, the ultimate support being the support of the motor, and to prevent the communication of any vibration either to the floor or to the case of the organ, Within which both the fan and motor may be inclosed,

the motor is provided with rubber feet a a, as seen in Fig. l.

I claim- 1. An organ-fan comprising a suitable case and a rotary fan-wheel Within the case having its vanes laterally inclosed throughout their Whole length and their edges at their outer ends oblique to the plane of rotation.

2. An organ-fan comprising7 in combination with a suitable case, a fan-wheel within the case having its vanes laterally inclosed between the disks of the wheel, said vanes being curved in the plane of rotation and having their edges at their outer ends oblique to the plane of rotation, whereby the air is drawn through the fan by its rotation Without tendency to pulsate or vibrate With musical tone.

In testimony whereof I have hereunto set my hand, in the presence of two witnesses, at Chicago, Illinois, this 3d day of August, 1895.

MELVILLE CLARK.

Witnesses:

CHAs. S. BURTON, Jos. SCHNEIDER.

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