US2931562A - Desk air fan - Google Patents

Description

April 1960 Y J. c. WISTRAND 2,931,562

nzsx AIR FAN Filed Jan. 20, 1958 5 Sheets-Sheet 1 s fi 37c INVENTOR JOHN C. WISTRAN D BY M ATTORNEY DESK AIR FAN 3 Sheets-Sheet 2 Filed Jan. 20. 1958 FIG.

INVENTOR JOHN C. WISTRAND FIG.7

ATTORNEY April 5, 1960 Filed Jan. 20. 1958 J. c. WISTRAND DESK AIR. FAN

3 Sheets-Sheet 3 INVENTOR JOHN C. WISTRAND ATTORNEY United States Patent DESK AIR FAN John C. Wistrand, St. Paul, Minn., assignor to Brown 8: isigelow, St. Paul, Minn., a corporation of Minnesota Application January 20, 1958, Serial No. 709,991

7 Claims. (Cl. 230-117) This invention relates to a new and improved air circulator; in particular it concerns a novel fan intended for tween otfice desks, night stands and other places where a relatively flat surface is available.

Small sized air circulators enjoy wide use and popularity in most sections of the country today. They are utilized both as a primary source of human comfort by providing evaporative cooling and are also used as a means for redistributing air that has been cooled by other means such as air conditioners and the like. However, prior art devices of the type similar to the one described herein have been characterized by features intended mainly to meet the problem of circulating air per se. That is to say, no particular attention has been given to the thought of moving an air mass in a spatially restricted zone in order to protect papers and light objects that are located near the air mover. In fact, the majority of todays desk fans and small air circulators discharge air from their outlets quite indiscriminately often resulting in the scattering of papers and general disturbance of all light weight objects within range if other preventive measures havent been taken. Many of such devices are equipped with horizontal and vertical adjusting means but even these have not fully solved the problem as the air is still discharged in a loosely defined unrestricted manner. Prior art fans are generally of the propeller type having a blade which revolves within a wire framework mounted upon a pedestal. Although such fans provide a mode of distributing air, they are usually quite noisy and may become very dangerous if care is not exercised when the blades are in motion. Furthermore, besides the danger of getting a finger caught in the blades there is always the possibility of having loose papers and other light objects caught up in the fan and destroyed.

Accordingly, it is a broad object of this invention to provide an improved desk air fan;

Another object of this invention is to provide an improved air circulator for use on relatively flat surfaces such as ofiice desks;

Still another object of this invention is to provide in a desk air fan means for confining the distributed air within spatial limits;

Another object of the present invention is to provide in a desk air fan means for adjustably controllingthe path of air circulated therefrom;

Yet another object of this invention is to provide in an air circulator novel intake and discharge means;

Another object of this invention is to provide a fan having improved safety features;

A further object of the present invention is to provide a desk air fan characterized by simple constructional features and an overall pleasing exterior appearance; A still further object of thisinvention is to provide a desk air fan that is relatively dust and dirt proof;

' Another object of the present invention is to provide a desk air fan that iscompact and easily transferred from I one location to another;

Yet another object of the present invention is to provide a substantially unitary structure for enclosing the components of a desk air fan;

Still another object of the present invention is to provide a desk air fan having convenient controls for adjustment and operation;

Another object of the present invention is to provide an air circulator having all moving parts completely enclosed for safety and for the exclusion of loose objects and foreign matter.

Another object of this invention is to provide a desk type air circulator suitable for ofiices, hospitals and the like where quietness of operation is a primary factor.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings in" which is shown an illustrative embodiment of the invention.

In the drawings:

Figure l is a plan view of the fan;

Figure 2 is a front elevation of the device;

Figure 3 is a side elevation of the invention;

Figure 4 is a top view of the fan with the cover removed;

Figure 5 is a sectional view taken along the line 5-5 of Figure 1;

Figure 6 is a sectional view taken along the line 6-6 of Figure 1;

Figure 7 is, a bottom view of the device;

Figure 8 is a perspective view of the device on a somewhat reduced scale; and Figure 9 is an exploded view illustrating the invention.

As shown in the several figures, the invention is char acterized by an outer casing generally designated by the reference character A. In its exterior appearance the desk air fan exhibits two well defined cavities molded together in an harmonious manner to provide space for the driving means and a chamber for the air distribution means. The motor unit for the fan is situated in the lower bowl shaped portion 12a of easing A while the impeller is located in the upper section 16. Suitable means are also provided for allowing air to pass through the structure with a minimum of frictional losses. It should be noted that in the design of the fan attention has been given to requirements dictated by aesthetic considerations as well as those concerning its functional behavior.

Casing A, preferably molded of a suitable plastic material such as polystyrene, super dylan polyethylene and thelike, is made in two sections, viz., upper cover 10 and lower casing 12. Upper cover 10, illustrated more clearly in Figure 9, has a substantially flat top surface 10a with depending wall 10b molded integrally therewith. Suitable threaded bosses 43 are located on the internal edge of wall 1% to allow the fastening of upper cover 10 to lower casing 12. Internal guide ribs 37 are integrally formed at the discharge end of upper cover 10 to receive discharge grid 36 when the unit is assembled. Suitable locking means are aifixed to the rear of upper cover 10 which mate with complementary means on lower casing 12, as will be explained.

Lower casing 12 has a somewhat bowl-shaped lower portion 12a which terminates at its upper extremity in a thin horizontally enlarged upper section 12b. Upper section 12b is designed to provide a chamber 16 for the impeller 35 and aflat surface 16a for the associated baffling that is necessary for the proper distribution of the air. Four vertical hollow bosses 43a are spaced along the inner wall 16b in register with threaded boss 'es 4 3 of upper cover 10 to allow fastening by means'of ribs 37 of upper cover 10 to position grid 36 securely 3 in pllace when upper cover is fastened to lower casing 2.

A thin rectangular shaped grid 36 having horizontal and vertical members 36a spaced in a lattice type arrangement fits into the discharge opening formed between upper cover 10 and lower casing 12. As pointed out previously, guide ribs 37 and 37a restrain grid 36 in place.

Lower portion 12a provides a housing for the driving and control mechanism and includes motor chamber 14 which is formed by lower side walls 15 and front and rear walls 17 and 18 depending downwardly from the under surface of upper section 12!). Side walls 15 are substantially symmetrical and extend at a slight angle as disclosed in Figures 5 and 7. Front wall 17 is vertical while rear wall 18 extends from the undersurface 13 at a rather sharp angle, as more clearly shown in Figures 3, 6 and 7. The bottom 19 of lower portion 12 is horizontal and has aflixed to its outer surface two rubber bumpers 21 at the rear and an adjusting screw having a projecting knob 20a at the forward end to provide a three-point resting surface for the device.

As illustrated in Figures 7 and 8, side walls 15 and rear wall 18 are curved slightly to enhance their appearance and to lend structural rigidity to the casing. Rear wall 18 is provided with a plurality of spaced curved parallel openings ll which provide an inlet for the ambient air. The slightly curved shape of openings 11a offer less resistance to the incoming air. Additional apertures 13 (Figure 7) essentially rectangular in shape, are located on bottom surface 19 adjacent the forward portion thereof to allow part of the incoming air to pass over the motor components for cooling purposes.

Four hollow cylindrical mounting posts 23, having a plurality of annular fins 23a on their upper exterior surfaces, are fastened to the internal surface of bottom 19 by bolts 27 (Figure 9). Each post 23 is threaded internally and has a thin circular shoulder with a fiat undersurface 23b near the lower end. Rubber grommets slide over and engage the lower end of post 23 at surface 23b to provide shock mounting for motor 28. The finned surfaces 23a of post 23 permit effective dissipation of a large share of the heat generated by motor 28 and they also serve to insulate casing A from elevated temperatures.

Motor 28 is preferably an alternating current shaded pole air cooled induction motor designed for 115 volt 60 cycle operation. It has a full load speed of approximately 3000 rpm. and draws about one-half ampere of current under full load conditions. Machine bolts 29, which extend through holes drilled in the field stack of motor 23, are threaded into the upper end of post 23 to secure motor 28 to bottom 19. An aluminum sheet (not shown) may be attached to the motor to provide electrical shielding for motor 28. A plastic lamp cord 34 is attached to the motor and extends through rear wall 18 terminating in a conventional prong type plug (not shown) for insertion in an electrical outlet.

Two four-position rotary switches 30 and 32, located on front wall 17, are conected electrically to motor 28 allowing the motor to be turned on and off and also providing for two speed operation. Switch 30 is the enabling switch while switch 32 reduces the speed of motor 28 by about one-half upon selection of the lower speed. The switches have plastic knobs 30a and 32a to allow ease of manipulation. A decorative panel 33 may be clipped to front wall 17 to provide a contrasting background for the switches and the directions associated therewith.

To separate motor chamber 14 from impeller chamber 16 a thin bafile 37 is provided which may be staked into place on horizontal shelf 16a of lower casing 12 or it may be glued thereto by means of a suitable adhesive. For purposes of vibration control as well as for economy and convenience the latter construction is preferred. Bafiie 37 is preferably fabricated of light sheet stock aluminum which is known for its easy workability and non-magnetic properties. Suitable recesses 37 for bosses 43a are cut into baffle 37 and a large circular opening 37b, positioned in axial alignment with motor shaft 26, is provided to allow impeller 35 to engage shaft 26. Opening 37b also serves as a passageway for the incoming air which is drawn up from chamber 14 by impeller 35. Vertical vanes 38:: and 33b are positioned on the impeller side of baflie 37 to direct the air How in the proper manner.

As can be seen in Figure 9, shaft 26 of motor 28 protrudes vertically through baflie plate 37 into impeller chamber 16. Impeller 35 is positioned on the top of shaft 26 and is secured thereto by means of hub 22 (Fig.- ures 5 and 6) which is pressed into the center of impeller 35 and fastened to shaft 26 by set screw 22a. Impeller 35 is preferably fabricated of high impact plastic material and has four radial vertical blades 35a that depend downwardly from horizontal circular disk-like member 35b.

Single vertical vane 38a and double vane 38!) are upturned on baffie 37 so as to direct the flow of tangentially swept air from impeller 35 in the manner best suited for the operation of a desk air fan, via, a straight beam of air confined vertically by the undersurface of cover 10 and the top of bafiie 37 and horizontally by the walls 16!) of impeller chamber 16. Figure 4 clearly illustrates the novel air flow characteristics of the device. It should be noted that the axis of impeller 35 is eccentrically positioned with respect to the axial symmetry of impeller chamber 16 with the result that a volute B diagrammatically shown in Figure 4 is formed for the passage of air from impeller 35. As shown, the rotation of impeller 35 is clockwise when viewed from the top.

Ambient air is drawn from the region adjacent the fans undersurface into air inlets Ila and 113 in the lower casing and up through opening 37b of baflie 37. Upon striking the under surface of disk 35!; the incoming air is directed from a substantially upward vertical direction into a substantially outward horizontal direction. Such a pronounced right angle change of direction is more efficient than a gradual transition with its attendant losses due to fluid friction. The abruptly turned air mass is then forced into volute B which forces it to flow according to the air flow characteristics of a conventional volute. That is to say, the scroll-shaped volute B, defined by the walls of the impeller casing, permits a reasonable velocity of emission from the fan outlet. The proportioning of volute B, as shown in Figure 4, also provides a gradual reduction of the emission velocity and converts an appreciable portion of the initial velocity pressure into useful static pressure. This is in contrast with those fan outlets which discharge directly into the atmosphere or to a large plenum chamber resulting in the almost complete waste and dissipation of the velociy pressure. Moreover, the intensity of sound emission is low due to the fact that the fan operates at a point near the peak of its static efliciency, and secondly, the complete enclosure of all moving parts tends to dampen the noise caused by the rotating elements. The rubber mounts for the motor and the rubber bumpers on the bot tom surface also contribute to the low sound level observed when the fan is in operation. The vaned construction permits the air to be discharged from the grid in a unitary path located well above the resting surface of the fan.

Single vane 38a, which is formed from 2. turned up portion of baffle 37, directs the air from a tangential direction causing the air to flow evenly towards the discharge grid 36 of the fan. Double vanes 38b, consisting of two vertical deflectors, are positioned, as shown in Figure 9, to deflect the resulting air stream into a well defined channel through grid 36. Grid 36, which is formed of plastic material, diffuses the air to creat a rip pling effect immediately adjacent the discharge area, con-.

tributes to the overall appearance of the invention, and prevents injuries which might result from tampering with the revolving impeller.

Upper cover is provided with a latch 31 (Figure 6) at the rear thereof which engages lug 40 in housing 12 to hinge the two pieces together. Machine bolts 45, which extend through bosses 43 of lower casing 12 are threaded into bosses 43 of cover 10 to hold the assembly together.

The resulting device is a novel fan having characteristics peculiarly adapted for use on desks and the like Where there is a chance of loose papers flying about because of the air movement. The air entering the base through apertures 11 and 13 is circulated and beamed in a personally controlled stream through the grid 36. A turn of the control switch 32 lets the user adjust the circulating air to a gentle breeze or brisk stream at his discretion. Thus it can be seen that the air stream is controlled so that important papers only inches beneath the device are undisturbed by the steady stream of cooling air. At a distance of two to three feet from the grid a light piece of copy paper set just under the air stream wont flutter. In adjusting the air current the adjusting screw 20 is turned either in or out to lower or raise the discharge end of the fan.

Besides being functional in nature, the device is also virtually tamper proof as no opening in the casing is large enough to allow fingers to enter. In addition, the arrangement of the inlet openings as well as their size prevents papers from being inadvertently destroyed by the impeller blades.

There has thus been described a new and improved type of air circulator inherently free of most of the troublesome features of an ordinary fan having propeller type blades enclosed in a cylindrical wire cage. The casing provides protection from dust and dirt as Well as being demonstrably safe in operation. Furthermore, the air flow characteristics are felt to be unique in the art of small desk type air circulators.

Although the invention has been described with a certain amount of specificity it is to be understood that the present disclosure has been made by way of illustration only and the scope of the invention is not to be limited thereby but is to be interpreted in the light of the appended claims.

I claim:

1. An electric fan for use on relatively fiat surfaces including an outer housing having a large upper compartment mounted over a smaller lower compartment, said compartments being substantially vertically symmetrical about the longitudinal axis thereof, a bafile separating the compartments of said housing, said baflle having a circular opening positioned in a rearward asymmetrical relationship with respect to the longitudinal axis of said housing, a motor in said lower compartment having a vertical shaft coaxial with the center of the opening in said battle and extending therethrough, an impeller attached to said shaft, said impeller including a backplate and radial blades integrally depending downwardly therefrom, a plurality of spaced inlet openings in said lower compartment, said large upper compartment having a substantially rectangular discharge opening in spaced relation above and forward from said lower compartment, a removable grid positioned in the discharge opening of said upper compartment, the walls of said upper compartment defining a volute with respect to said impeller, and vaned guides attached to said bafile adjacent the volute and the discharge opening of said upper compartment for deflecting air from said volute into the discharge opening.

2. An air circulator including a molded integral housing having a cover removably attached to the top thereof, said housing including a relatively shallow upper chamber, said upper chamber being characterized by a vertical integral wall defining straight substantially longitudinal side portions and an arcuate rear portion, said integral wall terminating at the front of said chamber to define in association with said cover a rectangular opening of greater length than width, said housing further including a lower chamber of greater depth and lesser width and length than said upper chamber, the lower chamber having a substantially vertical front wall and inclined side Walls, the lower chamber having a curved rear wall and a substantailly horizontal bottom surface, a partition between said upper and lower chamber, said partition having a passageway between said upper and lower chambers, an electric motor mounted in said lower chamber, said motor having a shaft extending through said passageway and terminating in said upper chamber, finned motor mounts for reducing the vibration of said motor during the operation thereof mounted on the bottom surface of said lower chamber, an impeller in said upper chamber rotatably mounted on the shaft of said motor, said impeller being disposed above the passageway of said partition and within the arcuate rear wall of said upper chamber to form a spiral volute therewith for channeling air toward the rectangular opening of said upper chamber, vanes disposed near the impeller and the rectangular opening of said housing for deflecting air from said impeller to said rectangular opening in said upper chamber and a grid removably positioned at the discharge opening to modulate the air flowing therethrough.

3. A dual chambered electric fan adapted to be supported on a flat surface comprising a base plate for supporting said fan with ventilating louvers therein, substantially vertically extending side, rear and front panels joined to the outer edges of said plate for forming an open topped lower chamber, said rear panel having a plurality of vertically spaced curved parallel slots for admitting ambient air into the lower chamber, a partial horizontal wall integrally joined to the upper edges of each of said panels and extending outwardly therefrom a substantial distance, vertically extending parallel side walls and an arcuate rear wall joined to the outer edges of said partial wall and a planar top wall joined to the upper edges of said rear and side walls, said partial, top, side and rear walls forming an upper chamber with a truncated completely open front of rectangular cross section, the open front disposed in spaced relation substantially above and forwardly from the front portion of said base plate, a removable grill member positioned in the open front and secured to said side, top and bottom walls and impeller means adjacent said arcuate rear wall for moving air up from the lower chamber and out the open front of the upper chamber, whereby the air expelled from said fan by said impeller is in a substantially rectangular pattern in spaced relation from said base plate and supporting surface.

4. An air circulator comprising a lower section having apertures therein for allowing an inlet stream of air to enter and pass therethrough in a vertical direction, an upper section positioned over said lower section for receiving the inlet air stream having an arcuate rear portion and an open truncated forward end of rectangular cross section, a rotatable impeller positioned asymmetrically in the arcuate rear portion for forming a volute of increasing width therewith, said impeller having a horizontal circular plate and a plurality of vertically dependent blades extending from the plate for providing a horizontal direction to the vertical inlet air stream through the volute and increasing the velocity thereof, first guide means positioned adjacent said impeller at the widest end of the volute to angle the horizontal air stream provided by said impeller toward the truncated end of said upper section and second guide means positioned in the open truncated end of said upper housing for directing the horizontal air stream outward from said circulator at right angles to the open end of said upper section.

5. A two chambered electric fan comprising a lower chamber having a base plate and substantially vertical side, rear and front walls extending upwardly from the base, the rear wall and base having apertures therein for the admittance of ambient air, an electric motor mounted on the base plate of said lower chamber, means for controlling said motor mounted on the front wall of said lower chamber, a horizontally disposed bafile mounted over the top of said lower chamber, said baffie having a circular aperture disposed in rearward asymmetrical relation with the vertical axis of said fan for providing an opening into said lower chamber, an upper chamber coextensively positioned over and around the sides of said battle and in symmetrical relation above said lower chamber, said upper chamber being of hollow rectangular cross section and having an arcuate rear portion integrally formed with a parallel side forward portion, the front end of the forward portion being completely open and forming a truncated leading edge disposed in spaced relation above and forwardly from the front wall of the lower chamber, an impeller for moving air from said lower chamber out the open front of said upper chamber, said impe ler mounted concentrically over the aperture of said battle and positioned in the arcuate rear portion of said upper chamber for forming a spiral volute of increasing width therewith, a vertical shaft passing co-axially through the circular aperture for rotatably connecting said motor to said impeller, a pair of vertical vanes mounted on the upper face of said battle at the open leading end of said upper chamber and directly forward of said impeller for directing air out of said upper chamber and a single vertical vane mounted on the face of said battle at the wide end of the volute formed by said impeller and upper chamber for angling air from the volute toward said pair of vertical vanes.

6. A fan comprising a housing having an upper and a lower chamber, the upper chamber having a rectangular opening in spaced relation out from and above said lower chamber; an electric motor mounted in the lower chamber and having a shaft extending into the rearward portion of the upper chamber; an impeller mounted on the upper end of the shaft of said motor for rotation within said upper chamber; a thin horizontal bafile having an opening coaxial with the shaft of said motor for partitioning the upper and lower chambers of said housing and vertical deflectors positioned on the upper surface of said bafiie adjacent said impeller and a rectangular opening of the upper chamber for deflecting air out from said fan.

7. A fan for emitting a flow of air in spaced relation above a flat surface, comprising a lower chamber for housing an electric motor and means for controlling said motor; an upper chamber of substantially greater extension along a horizontal plane than said lower chamber, said upper chamber having an arcuate rear Wall and a truncated leading edge, the leading edge extending beyond both sides of said lower chamber and positioned in spaced relation above and forward from said lower chamber; an asymmetrically positioned impeller connected by a shaft to said motor and disposed adjacent the arcuate rear wall of said upper chamber for forming a volute therewith; a planar bafi le coextensive with the bottom of said upper chamber for separating said upper chamber from said lower chamber and vertical vanes on the surface of said bafile along the leading edge of said upper chamber and adjacent the impeller and volute for deflecting air from the impeller and out from the leading edge of said upper chamber.

References Cited in the file of this patent UNITED STATES PATENTS D. 156,294 Trow Nov. 29, 1949 D. 181,185 Collins Oct. 15, 1957 2,160,278 Ness et al. May 30, 1939 2,341,974 Browne Feb. 15, 1944 2,440,363 Briskin Apr. 27, 1948 2,565,769 Hatker Aug. 28, 1951 2,710,717 Palmer June 14, 1955 FOREIGN PATENTS 538.038 Canada Mar. 12, 1957

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