US1757292A - Cooling fan - Google Patents

Description

FAN

L L E w D L A G F.

COOLING Filed Nov. 3, 1921 1930. F. W. CALDWELL COOLING FAN Filed Nov. 3, 1921 2 Sheets-Sheet 2 H074 TIONAL I VELOCITY All? 1 /7555 U/PE HUMTIUNAL VEL OC/TK 5] wuento'c Patented May 6, IQSO I UNITED STATES PATENT; OFFICE FRANK W. CALDWELL, OF DAYTON, OHIO COOLING FAN Application filed November 3, 1921. Serial 1T0. 512,408.

This invention relates to fans and more views illustrating the action of centrifugal particularly to a cooling fan for an autoforce on the blade. mobile engine. In these drawings I have illustrated one The greatest need for the cooling fan for embodiment of my invention and have 5 an automobile engine occurs when the autoshown the same as comprising a fan in which 50 mobile is moving at a relatively slow speed each of the blades is mounted for movement with the'engine'under aheavy load, as when about an axis extending lengthwise of the the car is climbing ahill on high gear, Whe blade. The movement of the blades about the automobile is runnin atarelatively high ir respe tive longitudinal axes is conspeed enough air flows t rough the radiator, trolled by a suitable yielding device which 55 as a result of the speed of the automobile, wlllretain them in their normal, or operato provide ufli i nt o li f th i tive, positions until the engine has reached Inasmuch as th f b b a great d l a predetermined speed and which will then of power it is desirable that it should be so Permit them to rotate about Said longitudinal controlled a to Save thi power h th f axes into ppsitions which will so alter the 60 is-not needed for c li pm-P0ses 7 blade angles as to cause the same to operate One object of th i ti i t id a as a w1nd mill. It Wlll be understood that fan of such a, character th t, h th t the articular embodiment here illustrated mobile is moving at such a speed that the fan h n Chosen t Pl p of mustm' i t i d f li purposes it ill tron only and that the fan itself may take va- 65 absorb littl no power f th i rlous forms and the detallsof constructlon It is a further object of the invention to may be wldely flamed from these hereshewnprovide suchafan in which the blade angles In thetipel'tleuler tern? of the devlee here of the fan will be automatically-altered, when Illustrated the fan cemPmseS P' the automobile reaches a certain predeter- P g Struetllre, Whleh 15 1 70 mined speed, to cause the fan to operate as a Dated In a e g 23nd may be epemtlvely .wind mill, so that no engine power is reconnected Wlth asource of POYV Such as an qui d t Operate in automobile eng ne, in any suitable manner.

A further object of the invention is to pro .'Mounted on thls hub are more ten vide a fan of this kind which will be simple the P n havmg four, and in its construction and operation and which e Q these blades rotatable atflmlt may be easily maintained in an operative axle extendmg tengthwflse 'e re thls diti end each blade is provided at its inner end Other objects of the invention will appea with trunnion which is leul'neled in a as the device is described in detail. suitable bearing in the supporting structure, 0

In the accompanying drawings Fig. 1 is an hub, AS here h the PP e" end view of a fan embodying my invention; Structure 15 hollow, P p and t Fig. 2 is a sectional-view taken centrally tl'lmmons extent; q g t e f' through the hub of such a fan; Fig. 3 is a and are e 1n posltwn 1n bearmss 40 transverse section taken on the line 33 of y cellars 5 g e y Secured t t ends 85 Fi 2; Fi 41 a did ti l i h thereof If desired, antlfrlctlon bearings 6 ing a section of a fan blade in its normal y be mterposed between the e e and the iti Fi 5 1 a imi w Showing h hub structure to reduce the frictional consection'of the fan blade inits reverse positact between these P 45 tion; and Figs. 6 and 7 are. diagrammatical Smteble means are Prevlded for heldmg 'ture. This stud is arranged centrally of the supporting structure and has rotatably 'mounted thereon a sleeve 8 having at its outer end a circumferential fiange9 which are provided a plurality of recesses 10, there being one such recess for each blade. The inner end of the sleeve is recessed, as shown at 11, and the end walls of this recess serve as stops which cooperate with a fixed stop, or lug, 12, carried by the end wall of the hub structure and extending intothe recess. Each fan blade is connected with the sleeve so that the rotation of the fan blades about their longitudinal axes will impart-rotatory movement to the sleeve. As here shown, the

collar 5 of each bla'dehas rigidly secured thereto an arm 13, the outer end of which extends into the corresponding recess 10 in the flange of the sleeve. Preferably the outer ends of the arms 13 are spherical to reduce the frictional contact between the same and walls of the recesses. The ieeve,

and consequently, the'blades-are held normally against rotatory movement by means of a spring 14 which is coiled about the outer end portion of the stud, or shaft, 7 and has one end secured to the sleeve and the other and secured to a collar 15 which is rigidlysecured to the stud, or shaft, 7. I The tension of the spring may be regulated by adjusting the collar 15 on the stud 7 and to this end the collar is screw threaded onto the stud and then secured against rotation by means of a pin 16.

In the present construction centrifugal force is utilized to rotate the fan blades about their longitudinal-axes andthus alter the blade angles. The action of the centrifugal force on the blade may be explained by reference to Figs. 4: and 7. Fig. 4 shows the air force acting on a section of an ordinary fan blade and it will be apparent that the air pressure on the blade is such as to resist the revolution of the fan. In Fig. 5' the angle between the blade section of the fan and the plane of revolution has been reduced to such an extent that the air pressure will be substantially. reversed and will cause the fan tofunction as a wind mill. With the blade in the position shown inFig. 5 it will be apparent, therefore, that the air flowing through the radiator of an automobile moving at high speed will assist the revolution of the fan to such an extent that little or no power will be requiredto operate the same.

As has been stated, centrifugal force is utilized to so alter the blade angles and in Fig. 6 I have shown a plan view of a typical fan blade which may be considered as dimay be taken as equal to D-F, and will have a component D-B which is perpendicular to the center line of the blade.

If these components are now transferred to the sectional view in Fig. 7 it will be obvious that they act upon the respective portions of the blade in opposite directions and thus tend to produce a twisting movement which will reduce the angle between the blade section and the plane of revolution. This twisting movement is produced by the centrifugal force and is proportional to the square of the revolutions. Obviously as the speed of the engine increases the centrifugal force on the fan blades will increase until when the automobile reachesa speed-at which the fan is no longer necessary for cooling purposes the twisting action of the centrifugal force on the blades will be suflicient to overcome the tension of the springlet, thus permitting the blades to move from the position shown in Fig. 4 to the position shown in Fig. 5 and converting the fan into a wind mill which will be operated by the flow of air through the radiator, thereby greatly reducing, or entirely eliminating, the absorption of power" by the fan from the engine. When the blades have moved to the desired position their further rotation is prevented by the stop 12, and as the speed of the engine falls the blades will be returned to their normal positions by the action of the spring 14', the movement in this direction also being limited by the stop 12.

While I have shown and described one embodiment of my invention I wish it to be understood that I do not desire to be limited to the details thereof as various modifications may occur to a person skilled in the art.

Having now fully described my invention what I claim as new and desire to secure by Letters Patent, is: V 1. In a fan, arotatable supporting structure, a blade mounted on said structure for movement by the action of centrifugal force thereon about an axis extending lengthwise of said blade and held against longitudinal. movement, a member rotatable with relation to said supporting structure about an axis extending transversely to said axis of said blade, an operative connection between said blade and said member, and a spring acting on said member to resist its rotation by said blade.

2. In a fan, a rotatable supporting structure, a blade mounted on said structure for movement by centrifugal force about an axis extending lengthwise of said blade, a stud carried by said supporting structure, a member rotatably mounted on said stud, an operative connection between said member and said blade, and a spring coiled about said stud and connected at one end with said memher and at the other end with said stud.

3. In a fan, a rotatable supporting structure, a blade mounted on said structure for movement by centrifugal force about an axis extending lengthwise of said blade, a stud rigidly secured to said supporting structure, and extending transversely to the axis of said blade, a part rotatably mounted on said stud and having a recess therein, an arm extending radially from said blade and having one end arranged in said recess, and a spring coiled about said stud and connected at one end with said part and at theother end I with said stud.

4. In a fan, a rotatable supporting structure, a blade mounted on said structure for movement b centrifugal force about an axis extending lengthwise of said blade, a stud rigidly secured to said supportin structure, and extending transversely to t e axis of said blade, a part rotatably mounted on said stud and having a recess therein, an

arm extending radially from said blade and having one end arranged in said recess, and a spring coiled about said stud and connected at one end with said part and at the other end with said stud, and a stop for limiting the movement of said part.

5. In a fan, a hollow supporting structure having an axial stud rigidly secured thereto, a plurality of fan blades mounted on said supporting structure for movement about axes extending lengthwise of the respective blades, a sleeve rotatably mounted on said stud and having at one end a flange rovided with recesses, an arm rigidly secure to each blade and having its end extending into one of said recesses, a stop to limit the rotation of said sleeve, and a spring coiled about said stud and having one end connected with said sleedve and the other end connected with said stu 6. In a fan, a rotatable supporting structure, a blade mounted on said structure for movement about an axis extending lengthwise of said blade, a stud carried b said supporting structure, a member rotata ly mounted on said stud, an operative connection between said member and said blade, and a spring acting on said member to resist its rotation by said blade.

7 L In a fan, a rotatable supporting structure, a blade mounted'on said structure for movement about an axis extending lengthwise of said blade, a stud rigidl secured to said supporting structure an extending transversely to the axis of said blade, a part rotatably mounted on said stud and having a recess therein, an arm extending radially from said blade and having one end arranged in said recess, and a spring coiled about said stud and connected at one end with said part and at the other end with said stud.

8. In a cooling fan for an automobile engine, a fan blade mounted for bodily movement'about an axis extending transversely thereto and for movement about a longitudinal axis located between the lateral edges thereof and in such relation to the mass of said blade that the movement of said blade about said transverse axiswill cause it to move about said longitudinal axis in a direction to decrease the angle thereof as the speed of movement about said transverse axis increases, and means to restore said blade to its initial position with relation to said longitudinal axis.

9. In a cooling fan for an automobile engine, a fan blade mounted for bodily movement about an axis extending transversely thereto and for movement about a longitudi-' longitudinal axis until the movement about said transverse axis reaches a predetermined speed.

10. In a cooling fan for an automobile engine, a fan blade held against longitudinal movement and mounted for bodily movement about a transverse axis and for movement about a longitudinal axis located between the lateral edges thereof and in such relation to the mass thereof that the action on said blade of centrifugal force resulting from the move ment thereof about said transverse axis will cause said blade to move about said longitudinal axis in a direction to decrease the angle thereof as the speed of movement about said transverse axis increases, and yieldable means to resist the movement of said blade about said longitudinal axis.

11. In a cooling fan for an automobile engine, a fan blade held against longitudinal movement and mounted for bodily movement about a transverse axis, and for movement by the action of centrifugal force thereon about a longitudinal axis in a direction to decrease the angle thereof as the speed of movement about said transverse axis increases, and means to control the movement of said blade about said longitudinal axis.

12. In a cooling fan for an automobile enine, a rotatable supporting structure,.a fan filade mounted on said structure for movement with relation thereto, by the action of centrifugal force on said blade, about a longi- 5 tudinalaxis in adirection to decrease the angle thereof as the speed of rotation of said supporting structure increases, and means for holding said blade against movement about said longitudinal axis until said supporting structure is rotated at a predetermined speed. In testimony whereof, I aflix my signature hereto.

' FRANK W. CALDWELL.

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