US2654533A - Protective guard for rotary fans - Google Patents

Description

Oct. 6, 1953 A. COLLINS 2,654,533

PROTECTIVE GUARD FOR ROTARY FANS Filed Feb. 27, 1950 2 Sheets-Sheet l INVENTOR Oct. 6, 1953 A. COLLINS I ,654, 3

PROTECTIVE GUARD FOR ROTARY FANS Filed Feb. 27, 1950 2 Sheets-Sheet 2 39a 36w 18 14 37 11a 2900 18 39a INVENTOR 66;, BY 3 hawk-L,

ATTORNEYJ Patented Oct 6, 1953 UNITED STATES PATENT OFFICE PROTECTIVE GUARD FOR ROTARY FANS Aubrey Lawrence Collins, Harrow, England Application February 27, 1950, Serial N 0. 146,582 In Great Britain March 7, 1949 12 Claims. 1

This invention relates to protective guards for rotary fans.

It is an object of the invention to provide an improved form of guard which is found to have important practical advantages as compared with the usual flat circular wire guard. Thus the improved guard reduces the nois produced by the air stream and at the same time enables increased fan efiiciency to be achieved. A robust construction of guard can readily be produced according to the invention, and where desirable the guard can be arranged to fold. The invention further sets out to provide an improved form of guard which is very pleasing in appearance and is adaptable to various types of ornamental treatment.

It is a further object of the invention to provide an improved form and construction of guard which is adapted to fit easily into a relatively small space and is therefore cheaper to pack than a corresponding fan of the usual construction, the chance of the guard being damaged in transit being correspondingly diminished.

It is found that the improved form of fan has a high operating efiiciency when the cage is constructed mainly of wires, so that it offers relatively small resistance to the air flow. Moreover noise is substantially reduced, probably owing to the fact that in the spherical form of cage the members are curved, and those which are disposed in the main air flow are all positioned some distance away from the plane of the fan.

The invention is illustrated in the accompanying diagrammatic drawings, in which:

Figure 1 is a front elevation of one form of folding fan unit;

Figure 2 is a side View thereof;

Figure 3 is a plan corresponding to Figures 1 and 2;

Figure 4 is a front elevation of the fan unit shown in its folded condition;

Figure 5 is a fragmentary side elevation showing how the arched members fold together;

Figure 6 is a fragmentary side elevation of a multiple hinge fitting for the arched member;

Figure 7 is a fragmentary side elevation of one of the bracing members;

Figure 8 is a side elevation of a modified construction of electric fan; and

Figure 9 is a plan of another construction embodying removable side members.

The electric fan shown mainly in Figures 1 to 4 comprises a rigid main portion which is indicated at H] and two collapsible or folding side portions II and Ha. The rigid main portion !8, which constitutes the middle part of the fan guard, is made up of two ring-like rib members l2 and 12a which are joined at the top and bottom by spacing members it and lie in parallel vertical planes. An electric motor is having a casing of streamline shape is disposed between, and rigidly secured to, the front parts of the two rib members l2, l2a, the axis I? of the motor being parallel with the planes of the ribs 52, 52a. Upon the shaft Iii of the motor M an impeller boss I! is secured, carrying two impeller blades I3. The boss I! is substantially cylindrical in external shape and its left-hand end is is of the same diameter as the adjacent inner end 2d of the motor I i, so that the external surface of the boss merges smoothly on to the outside of the motor it, thus producing good acre-dynamic efficiency. A somewhat frusto-conical core member 2| is fixed between the back portions of the rib members 12, Ila and has its front part 22 equal in diameter to the rear of the boss 6 i; thus the motor Hi, boss H and core member 2! together form a streamline core along the outside of which the air flows smoothly and efficiently owing to the impelling action of the blades as. The core member 2! is preferably a hollow casing containing any ancillary devices (not shown) re-- quired for the motor M, such as a capacitor, speed-controlling gear or a control switch. The rigid main unit it! also includes upper and lower intermediate rib members 23, 26 of arched shape, each having its front end attached to the motor I 4 at 25, while its rear end is secured to the core member 2!, both members 23, 2!! being firmly attached to the spacers E3 to produce a strong, rigid structure. The rib members 92, i2a are formed at their lower parts with rockers 28, 26a to act as feet, while a third point of support is provided by a leg 21 which is stifiiy pivoted at 25, 28c so as to be angularly adjustable for enabling the inclination of the axis is to be varied to suit requirements.

The side portion ll comprises a series of wire arch members 29-36 which are pivoted at the front ends to the front of the rib member 12 by a composite hinge device 3?; similarly their rear ends are pivoted to the rear of the rib member It by a hinge device 33. They are held in their angularly spaced operative positions, as shown in Figures 1 to 3, by an arcuate bracing member 39 which is of rectangular shape in section and has its ends pivoted to the rib member l2 about a common substantially vertical axis at $0 and 4!. As shown in Figure 7 the bracing member 39 has spaced notches :2 which engage with the corresponding arch members and hold them in their correct positions, the arch members being sufiiciently resilient to be sprung into place. The hinge device 31 is conveniently arranged in the manner shown in Figure 6. An attachment plate 43 has a pair of lugs M, 45 which are fitted with a pair of mutually parallel pivot pins 45, 51. The ends of the arched members 29-36 are drilled to fit snugly upon the corresponding pin 46 or 41. Thus by swinging the bracing member 39 into the general plane of the rib member I2, the arched members 29-35 can be laid upon it as shown in Figure 5, so that the whole of the parts forming the side portion II lie compactly against the rib member I2.

The side portion Hat is of similar construction and the parts are indicated by the same numerals with the sufiix a. When both side portions I I, I Ia are folded, the whole fan appears as shown in Figure 4, the impeller blades I8 being snugly accommodated within the main portion IE3, and the leg 21 being folded back against the outside of the lower spacer I3. The whole unit is therefore condensed into a rigid, robust assembly; it can therefore easily be packed without waste of space and also with considerably less risk of damage in transit than is possible with non-folding fans of the normal design.

It will be seen that when the side portions II and Ila are opened as shown in Figures 1 to 3 they combine with the rib members I2, I2a., the ribs 23, 2s and the spacers which is like a cage and is substantially spherical in shape, the general plane 48 of revolution of the impeller blades I8 being approximately coincident with the vertical diametral plane of the cage, of the portions I0, I I, Ila con and the rear parts stituting a hemi-sphere behind the impeller I'I, I8, i. e. on the air-intake side thereof. In the example shown, the front of the cage, is also of nearly hemi-spherical shape, but is formed with a dimple or reflex cusp where it is attached to the motor I4, thus producing a very attractive appearance, this dimple or reflex cusp is indicated at 49 in Figure 2. With this substantially spherical form of cage those parts past which the main air flow occurs (i. e. the parts within the cylindrical zone indicated by the broken line 50 in Figure 1) are widely spaced from the impeller blades I8;

moreover said parts are all curved and therefore are inclined at widely varying angles to the plane of rotation 48. These factors together have the efiect of substantially eliminating noise during running, the energy which would ordinarily be expended in creating air or mechanical vibrations being imparted to the useful air flow.

In the modified construction of electric fan shown in Figure 8 the main portion I0 is composed of spaced ring-shaped ribs I2, I2a as before held together by spacers (not shown) to form the middle part of the cage. The motor I6 is secured between the ribs I2, I211. and its shaft I6 is fitted with a blade impeller having a small boss I'Ib and two or more blades I'cb which rotate in a plane 4% disposed just forward of the diametral plane 50b of the cage. The side portions, one of which is seen in Figure 8, comprise a number of arcuate wires 5|, which have their ends secured to the front and back parts of the rib I2 and are held firmly in spaced relationship by an arched bracing member 52. The rib I2, wires 5| and the bracing member 52 may be rigidly and permanently secured together, or they may be pivoted so as to fold, as in the previous example. The ribs I2 and I2a are formed with lugs 53, 53a which are attached to a heavy stand 54 by a horizontal pivot 55, suitable clamping means (not I3 to form a guard shown) being provided. Thus the cage and motor can be tilted forwards or backwards and securely held at any desired inclination. In some cases the cage may be mounted upon the stand 54 so as to swivel relative thereto about a substantially vertical axis.

- Another modification is shown in Figure 9 and in this instance the side portions II, He are themselves rigid but are completely removable from the centre portion Ill. Thus the side portion Ii is a somewhat basin-shaped moulding or pressing 56 having a rim 51 which is fastened removably to the rib I2 by any suitable means (not shown) such as spring clips. Air intake slots or other openings 58 are provided, and the air stream, passes out through corresponding openings 59 in the front of the side portion H. The side portion I Ia is of similar construction. When the fan is to be packed, the members 56, 56a. are removed and fit one into the other to form a compact robust assembly; the center portion II) is, of course, very compact and contains the motor and impeller. Where the impeller has more than two blades it may be removed from the motor shaft for packing, although in the preferred arrangement the blades are made in pairs, which, when the usual clamping means are slackened, can all be brought into alignment within the centre portion Ill of the cage.

It will be understood that various modifications may be made and that the above details are given only by way of example. Any suitable form of pivotal mounting may be used for the ends of the arched wires, for instance slotted caps may embrace turned-out ends on the wires and may be secured to the rings by tabs or the like. Ball and socket joints may be used if desired. Sometimes the central section may be arranged horizontally, on folding section of the cage being disposed above and the other below.

What I claim is:

1. An electric fan having a motor, a rotary impeller driven thereby, and a protective guard surrounding said impeller, the guard comprising a rigid main portion which is flat in shape and has its general plane containing the axis of the motor and impeller, and a pair of side portions, each of said side portions comprising a plurality of arched members which are pivotally connected at their ends to the rigid main portion, and

are adapted to be moved angularly from a spread. operative position to a folded position in which they lie close against the main portion.

2. An electric fan according to claim 1, includ ing, for each side portion, a bracing member which intersects the arched members, and holds said arched members in their spread operative positions.

3. An electric fan according to claim 2, in which the bracing member is of arched shape, and pivots are provided at its ends connecting said ends of the bracing member pivotally to the main portion of the guard.

4. An electric fan according to claim 3, in:

which the bracing member has notches which interlock with the arched members to hold said arched members in their spread positions.

5. In an electric fan having a motor with a spindle and a bladed fan rotor mounted on said spindle, a guard assembly comprising a pair of foundation rings disposed in parallel planes at right angles to the plane of rotation of the fan rotor, the motor being disposed between said rings and being carried thereby, spacing means connecting said rings to form a compact rigid foundation framework, and a pair of rigid cupshaped side portions mounted upon the outsides of the respective foundation rings so as to extend laterally therefrom and guard the fan as its blades swing out sideways through said foundation rings, which rigid side portions are removable from the foundation framework, thus leaving said foundation framework, including the motor and fan rotor, as a flat compact unit for packing and storage.

6. In an electric fan having a motor with a spindle and a bladed fan rotor mounted on said spindle, a guard assembly comprising a pair of foundation rings disposed on opposite sides of the motor spindle and in parallel planes both parallel to said spindle, the motor being disposed between said rings, and the fan rotor being disposed inside said rings, means fastening the rings to opposite sides of said motor so that the motor is carried by said rings, spacing means connecting said rings to form a compact rigid foundation framework, and a pair of cup-shaped side portions mounted to extend sideways from the respective foundation rings and guard the fan as its blades swing out sideways through said foundation rings.

7. An electric fan as claimed in claim 6, having a core member disposed between the foundation rings in alignment with, and diametrically opposite to, the motor, and a rotating boss on the fan rotor, which rotating boss bridges the gap between the motor and the core member.

8. An electric fan as claimed in claim 6, having a core member disposed between the foundation rings in alignment with, and diametrically opposite to, the motor, and a rotating boss on the fan rotor, which rotating boss bridges the gap between the motor and the core member, the adjacent ends of the motor and fan rotor boss being equal in diameter, and the adjacent ends of said boss and the core member being equal in diameter, the exterior of the motor, boss and core member forming a smooth streamline surface.

9. In an electric fan having a motor with a spindle and a bladed fan rotor mounted on said spindle, a guard assembly comprising a ring-like foundation framework incorporating the motor, the axis of the motor spindle extending across the framework in the general plane of said framework, the fan rotor being mounted on said spindle at a position inside the foundation framework so that the fan blades turn in a plane at right angles to the general plane of the foundation framework, and a pair of cup-shaped side portions, each side portion comprising a plurality of substantially U-shaped wires having pivotal joints at their extremities attaching them to the foundation framework so as to enable them to fold flat against said framework, said side portions when in their operative positions extending laterally from the foundation framework so as to guard the fan as its blades swing out sideways from said framework.

10. An electric fan according to claim 9, in which the U-shaped wires of each side portion fold one inside another so that they all lie in a common plane when said side portion is folded.

11. An electric fan according to claim 9, wherein each side portion comprises a plurality of substantially U-shaped wires, pivotal joints attaching the extremities of said wires to the corresponding foundation frame, an arcuate bracing member, pivotal joints attaching the ends of said bracing member to the foundation frame, said bracing member when in its operative position being arranged to intersect the U-shaped wires and hold them in their operative positions.

12. An electric fan according to claim 9, wherein each side portion comprises a plurality of substantially U-shaped wires, pivotal joints attaching the extremities of said wires to the corresponding foundation frame, an arcuate bracing member, pivota1 joints attaching the ends of said bracing member to the foundation frame, said arcuate bracing member being formed in its outer curved edge with a row of notches arranged to engage respectively with the U-shaped wires and hold them in position.

AUBREY LAWRENCE COLLINS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,194,413 Nesseler Aug. 15, 1916 1,695,002 Xippas Dec. 11, 1929 1,975,934 Gilbert Oct. 9, 1934 2,105,315 Finch Jan. 11, 1938 2,183,979 Thornberg Dec. 19, 1939 2,259,853 Koch Oct. 21, 1941 2,463,337 Weber Mar. 1, 1949 FOREIGN PATENTS Number Country Date 625,522 Germany Feb. 11, 1936 626,965 Germany Mar. 5, 1936

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