US2192811A

US2192811A - Fan

Info

Publication number: US2192811A
Application number: US155673A
Authority: US
Inventors: Joseph H Cohen
Original assignee: Casco Products Corp
Current assignee: Casco Products Corp
Priority date: 1937-07-26
Filing date: 1937-07-26
Publication date: 1940-03-05
Anticipated expiration: 1957-03-05

Description

J. H. COHEN March'5, 1940.

FAN

Filed July 26, 1937 2 Sheets-Sheet 1 INVENTOR Josep/v H Cohen B j mama;

March 5, 1940 J. 'H. COHEN 2,192,811

FAN

Filed July 26, 1937 2 Sheets-Sheet 2 Fig. 7

Ill/I45 Fig. /0

INVENTOR I Joseph H Cohen Patented Mar. 5, 1940 UNITED STATES.

PATENT OFFICE FAN Application July 26, 1937; Serial No. 155,673

15 Claims. (Cl. 170-473) The invention relates to fans, and, more particularly, to fans for circulating air.

In mamng fans for circulating air, it is essential that the rotating elements be dynamically it'- balanced so that there will not be any whipping action .due to the uneven weight distribution when rotated at high speeds. Dynamic unbalance may be caused by several factors. One factor may be the mounting of the blades on the to hub improperly and unsymmetrically with respect to the axis of rotation of the hub. An- .other factor may be the means for mounting the hub upon the drive shaft of the motor.

With respect to the first factor, when blades it made of resilient material, such as rubber are used, dimculty has been found in adequately securing them to the hub so as to withstand the strain due to centrifugal force when the hub is rapidly rotated. This presents a problem since the fan blades must be uniformly secured to the hub in precisely the same manner so that their weight is properly positioned about the axis of rotation.

accordingly, the present invention provides blades which are adequately secured to the hub in such a manner as to be dynamically balanced and which are at the same time rigidly secured in place. A

In the preferred form of the invention, the hub t provided with slots of uniform width into which iierdble rubber blades are inserted from the back or inside oi the hub. The slots adjacenttheir forward end have recesses on their edgesand the blades are provided with projections on their side taces adapted to engage the recesses. This interlocking relation prevents the blades from slipalong the slots due to the rotating action of the fan and pressure oi the air on the blades as the blades are rotated. 0n the inner edge of the blade a plurality of projections or lugs are provided and the blade, adjacent each end, is provided with an ension lying in a plane of the blade. These projections and extensions engage the undersuriace of the hub adjacent the edges oi the slot and hold the blade from flying radially Y the clamping element so that it may be readily tram-the hub due to centrifugal force.

Another feature of the invention resides in the arrangement of the blades on the hub. According tothe present invention, three blades are dd positioned on the hub with their centers spaced 112W, apart. The blades are of such length that they extend around the hub for approximately 180. The blades are mounted so as to join the hub in a substantially helical path with the adjauu cent edges oi the blades in spaced overlapping re1ation.- This arrangement of the blades provides for an increased blade surface and permits the air drawn by this increased blade surface to flow freely through the fan so that more air is given for approximately the same expenditure d of energy, or a smaller motor can be used to obtain the circulation heretofore obtained.

It will be seen, therefore, that with the blades all made of the same material and of the same shape and secured symmetrically about the hub W that the rotating element will be in dynamic balance.

In another form of the invention the blade is molded so as to have a ridge adjacent to but spaced from the edge of the blade which is WW adapted to engage the hub. An insert of metal is molded in the blade along this edge to reinforce the same. The blade and insert are provided with holes positioned adjacent the ridge. Pins are provided to be inserted through the holes up so as to engage the inner surface of the hub to prevent the blades from flying out because of centrifugal force. Since the blades are made and secured inidentically the same manner, the rotating element will have a proper dynamic balance.

The second factor mentioned above for causing dynamic unbalance of the rotary elements resides in the manner in which the hub is secured to the shaft of the motor. If, for example, a so set screw is used, it is difiicult to get to for adjustment since a hole must be provided in the hub throughwhich an instrument can be inserted to turn the screw. Both the screw and hole in the hub will alter the weight of the hub so that some as provision must be made to counterbalance the same.

According to the present invention, the securing means is positioned in the hub so as to extend longitudinally of the hub along its axis of rotano tion. In this manner, unbalance of the hub is avoided and the necessity of counterbalancing is removed.

Another feature ofthe present invention resides in the mounting of the adjusting means for 45 Other features and advantages will be apparent from the specification taken in connection with the drawings, in which:

Figure 1 is a front elevation.

Fig. 2 is a side elevation.

Fig. 3 is a rear view showing the hub and blades.

- Fig. 4 is a side elevation of the hub.

Fig. 5 is a front view of the hub showing the arrangement of the slots.

Fig. 6 is a detailed section of the clamping means.

Fig. 7 is a sectional view of taken along line 'I'I of Fig. 1. t

Fig. 8 is a plan view of one of the blades.

' Fig. 9 is a section of the blade taken along line 9-9 of Fig. 8.

Fig. 10 is a section of the blade taken along line Iii-l0 of. Fig. 8.

Fig. 11 is a plan view of another form of blade,

Fig. 1215 a section of the blade shown in Fig. 11 with it in position on the hub.

' According to the present invention, a fan motor has secured to its bottom surface a plate 2| having a socket therein. The plate 2i may be secured to the motor housing in any desired manner, preferably bywelding. Mounted to pivot on the plate is a clamping member 22 adapted to extend into cooperative relation with the socket in the plate toreceive a supporting member 23 which is herein shown as having a ball fitting in the socket whereby the motor may be universally adjusted. =A screw 24 is threaded into the plate and extends through the clamping member to lock the motor in adjusted position.

hub and blades,

This motor mounting is specifically described and claimed in my divisional application .Serial No. 276,059, filed May 27, 1939.

A hollow cup-shaped hub is mounted at the forward end of the motor, and, as shown in Fig.

2, is shaped to slightly overlap the forward edge of the motor housing and tapers into a nose at the ,front of the fan. Dlmculty has been experienced in mounting such hollow hubs on the drive shaft of the motor so as not to destroy the dynamic balance of the rotating element. Accordingly, the hub is provided with an inwardly-extending sleeve 32, extending axially of the hub and concentric with the axis of rotation of the hub. This sleeve may be formed integrally with the hub or may be separately made and secured thereto. The sleeve has acamming surface 33 formed in its bore. Mounted to slide in the bore of the sleeve 32 is a clamping sleeve 34 having a bore of sumcient size to receive a. motor shaft 3i. The end of the sleeve, adapted to receive the motor shaft, is split so asto form a plurality of clamping elements 35. These clamping elements have camming surfaces 36 thereon, adapted to engage and cooperate with the carnming surface 93 within the sleeve when moved relatively there- 4 force when the blade is set in motion. vided with a wall having thgeads 91 therein which to. The other end of the clamping sleeve is proare adapted to cooperate with a bolt 39 mounted in a recess 39 at the nose of the hub so as to lie below the surface of the hub. The bolt extends along the axis of the hub and upon being rotated slides the clamping sleeve relative to the sleeve 92 whereby thecamming surface will move the clamping elements into clamping relation with the end of the motor shaft. Since all the elements are symmetrically positioned with respect 1 to the axis of rotation of the hub, the hub will always be dynamically. balanced.

A further feature of the invention resides in the accessibility of the bolt 39 whereby the hub may be clamped to the motor shaft. In'prior practice it has been customary to provide the hub with a sleeve similar to the present sleeve 32 and have a set screw therein adapted to be moved into engagement with the motor shaft. The hollow hub had to be provided with an aperture through which a tool could be extended to engage and adjust the set screw. Aside from destroying the balance of the hub, the set screw was very difllcult to reach when it was desired to attach or remove the hub from the shaft. According to the present invention, however, the head of the bolt is open to view and easy access since it is positioned adjacent the outer surface of the hub and may be readily operated to lock the hub to the shaft or remove the same therefrom.

This novel mounting for the hub is described and claimed in my divisional application Serial fan blades of the fan. The fan blades of the present invention, only one of each form being described, are made of resilient material, preferably rubber, and are tapered in cross-section as shown in Figs. 9, 10 and 12.

.In the preferred form of the invention, a blade 42 is made of flexible rubber and is adapted to be inserted from the inside of the hub. Adjacent its forward end or that end nearest the nose of the hub, the blade has a projection 43 extending from each face of the blade to engage the recesses 4| in the slot to hold the blade from sliding in the slot due to the pressure of the air on the blade when in operation. This effectively prevents shifting of the blade and thereby the weight distribution of the blade about the axis when such flexibility is not required. At each and of the engaging edge of the blade, a projection or wing 45 is formed in the plane of the blade and extends to engage the inner surface of the wall to further prevent the blade from being thrown outwardly through the slot by centrifugal Three such blades are used, and, according to the present invention, have their centers spaced about the hub at 120 apart. The blades extend around the hub for approximately 180 and have their adjacent edges in spaced overlapping relation. By using threei blades and positioning them in the manner shown in the drawings, a greater circulation of air is produced than heretofore obtained with approximately the same e penditures of energy. The blades are sufllciently separated to permit the air to freely flow through the fan and have suflicient surface to bite into and draw through a large amount .of air without undue resistance.

molded so as to have an outwardly-extending ridge 50 adjacent to but spaced from the edge engaging the hub. In the form disclosed, a metal insert it is molded in the blade in the hub-engaging section to reinforce the blade, although this is not essential as the blade is stiff enough,

and a plurality of holes 52 are drilled or punched through theplate and blade adjacent the ridge. The blade is mounted in the slot from the outside so that the ridge engages the outer surface of the hub.. A pin 53 is inserted through each of the holes and is adapted to engage the inner surface of the hub to hold the blade in position. Preferably, the blade is pressed inwardly through the slot to slightly compress the resilient ridges and the holes in the blades are designed so that the pin may be readily inserted when the blades are held in such position. After the pins have been inserted, the blades are released and the resiliency of the blade forces the blades outwardly through the' slot which will pull the pins into firm engagement with the inner surface of the hub and securely hold the pins therein against movement. I

Variations and modifications may be made within the scope of this invention and portions of the improvements may be used without others.

I claim:

1. In an electric fan, a hub provided with a plurality of blade-receiving slots of uniform width, the edges of the slots adjacent the forward end of the same being provided with recesses; blades mounted in the slots having projections adjacent their forward edges adapted to engage the recesses in the ,slot whereby the blade is prevented from sliding in the slot when in operation;'and means for holding the blades on the hub.

2. In an electric fan, a hub provided with blade-receiving slots; blades of flexible material mounted in the slots; means for locking the blades to the hub without affecting the flexibility of the same comprising a plurality of independent projections extending around the edge of the blade and adapted to engage the inside surface of the hub to hold the blade thereon.

3. In an electric fan, a hub provided with blade-receivingslots; blades of resilient rubberlike material mounted in the slots; means for locking the blades to the hub without impairing the resiliency of said blades comprising a plurality of pin-like projections extending transversely of the blade around the edge of the blade and adapted to engage the ins de surface of the hub to hold the blade' thereon.

4. In an electric fan. a hub provided with blade-receiving slots of predetermined fixed length; blades mounted in the slots; means for looking the blades to the hub, said means including a projection at each end of the blade extending in the plane of the same, the distance between the free ends of said projections being greater than the fixed length of the slots so that said projections when the blades are mounted in said slots engage the underside surface of the hub adjacent each end of the slot to hold the blade thereon.

5. In an electric fan, a hub provided with blade-receiving slots; blades mounted in the slots and having a ridge molded thereon adjacent to but spaced from the edge thereof and adapted to engage the hub; a metal insert molded inthedrawing the separable means into firni fengagemetal insert; and pins adapted to be inserted through the holes, when the blades are in assembled relation to engage the inner surface of I the hub to hold the blades to the hub.

6. In an electric fan, a hub provided with blade-receiving slots; blades o'f'resilientmaterial mounted in the slots and having a ridge molded adjacent to but spaced .from the edge thereof and adapted to engage the outer surface of the hub; a metal insert molded in the blade; the blade having holes positioned adjacent the ridge and extending through the blade and metal insert; and pins adapted to be inserted through the holes when the bladesare in assembled relation to engage the inner surface of the hub, the resiliency of the blades holding the pins in firm engagement with the hub.

7. In an electric fan, a hub provided with blade-receiving slots; flexible rubber-like blades mounted in the slots and havinga ridge molded thereon adjacent to but spaced from the edge thereof and adapted to engage the outer surface 8. In an electric fan, a hub provided with 30 blade-receiving slots; flexible rubber-like blades mounted in the slots and having a continuous ridge molded thereonadjacent to but spaced from the edge thereof and adapted to engage the outer surface of the hub; and separable means adapted to bemounted along the edge of the blade in contact with the inner surface of the hub to lock the blade to the hub.

9. In an electric fan, a hub having slots extending helically therealong; flexible rubber blades mounted in said slots; and flexible means for securing said blades in said slots without affecting the flexibility of said blades comprising a plurality of projections spaced along a thinedge of the blade.

10. In an electric fan, a hollow hub having blade-receiving slots therein; blades of flexible rubber-like material mounted in said slots, the edge of the blades engaging the hub being relatively thin, whereby the blade is very flexible and can be readily inserted in the slots from within the hub; and means adjacent said edge extending perpendicularly to the face of the blade at spaced intervals therealong for engaging the hub to lock the blade in the slot without impairing the flexibility of the blades. v

11.- In' an electric fan, a hub having bladereceiving slots therein; blades of flexible rubber like material mounted in said slots, the blades the slots and having a continuous ridge molded thereon adjacent to but spaced from the edge thereof and adapted to engage the outer surface of the hub; and means adapted to be mounted along the edge of the blade in contact with the inner surface of the hub to lock theblade to the slot, the resiliency of the rubber blade ment with the inner surface of the'hub- 14. In an electric fan, a hub provided with.

blade-receiving slots; blades of resilient flexible material mounted insaid slots to project from the outer surface of the hub; and means for holding the blades in the slots without affecting the flexibility'of the same, including a plurality of pin-like projections extending transversely of the blade, said projections being disposed along at least a portion of the edged the blade to engage the inner surface of the hub to hold the blade thereon.

15. In an electric fan, a hub provided with blade-receiving slots; blades of resilient flexible rubber-like material having a ridge formed thereon and providing an abutment for engaging the outer surface of the hub; and means for holding the blades in the slot without affectin the flexibility of the same, including a plurality of pin-like elements extending transversely of the blades and disposed along at least a portion of the edge for engaging the inner surface of the hub to hold the blade thereon.

JOSEPH H. COHEN.