US2590762A

US2590762A - Fan oscillating mechanism

Info

Publication number: US2590762A
Application number: US44302A
Authority: US
Inventors: Kenneth A Ellis
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-08-14
Filing date: 1948-08-14
Publication date: 1952-03-25
Anticipated expiration: 1969-03-25

Description

March 25, 1952 K. A; ELLIS FAN OSCILLA'l ING MECHANISM 3 Sheets-Sheet 1 Filed Aug. 14, 1948 NYBNTQM (fl-r-rannsy 5 Sheets-Sheet 2 Filed Aug. 14, 1948 March 25, 1952 K. A. ELLIS 2,590,762

FAN OSCILLATING MECHANISM Filed Aug. 14, 1948 s Sheets-Sheet 5 qamem gnhaujas ,QM W

Patented Mar. 25, 1952 UNITED STATES PATENT OFFICE The present invention relates generally to elec tric fans and more particularly to an oscillating mechanism therefor.

One object of the invention is to provide a fan oscillating mechanism constructed in a novel manner whereby the fan in which it is incorporated is oscillated, rotated continuously or is held stationary.

Another object is to provide in an oscillating mechanism for a fan a novel construction permitting of variation of the limits of the are through which the fan is oscillated.

A still further object is to provide a fan oscillating mechanism which permits of change of condition of operation of the fan at any time regardless of the position of the fan when such change is made.

Still another object is to provide a fan oscillating mechanism which permits operation of the fan to direct air moved by it always at a constant angle with respect to its support.

The invention also resides in certain novel structural features by which the foregoing are carried out.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which:

Figure 1 is a fragmentary elevation of a ,floor stand type fan embodying the present invention.

Fig. 2 is a fragmentary vertical section on an enlarged scale looking toward the observer as in Fig. 1.

Fig. 3 is a fragmentary transverse vertical section on an enlarged scale taken substantially on the line 33 in Fig. 2, but showing the fan motor and oscillating mechanism in elevation.

Figs. 4, 5, 6, '7 and 8 are horizontal sections taken substantially in the plane of line 4-4 in Fig. 2 and illustrating various positions assumed by the elements of the novel fan oscillating mechanism. Fig. 4 shows the positions for clockwise movement in oscillating condition of operation. Fig. 5 shows the positions for counterclockwise movement in oscillating condition. Fig. 6 shows the relationship of the elements for slow speed, counterclockwise, continuous rotation. Fig. 7 shows the element relationship for counterclockwise continuous rotation after passing one of the oscillation limit pins. Fig. 8 shows the positions of the elements for neutral or sta tionary operation of the fan.

While the invention is susceptible of various modifications and alternative constructions, .I have shown in the drawings and willhereinde- 10 Claims. (01. 2341:2515) scribe in detail the preferred embodiment, but it is to be understood that I do not thereby intend to limit the invention to the specific form disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

As illustrated in the drawings, the exemplary form of the invention is shown embodied in a fan of the floor-stand type which includes a housing I0 having a floor plate II and enclosing a motor l2. The latter includes a casing 13 and a shaft l4, the ends of which extend beyond the casing [3. The forward end of the shaft 14 projects through a vertically elongated slot IS in the housing l0 and has fixed thereon a propeller type blower l6. Secured to the motor casing l3 and disposed about the blower I6 is a guard cage H. The housing and the components associated therewith are rotatably mounted on a base 18 which, in turn, is fixed to a column or stand It].

To permit rotational movement of the housing and its associated components with respect to the base l8 and the stand l9, the plate I l is fixed on the upper end of a vertically disposed shaft 20 which rotates within a sleeve bearing 2| centrally disposed within the base I8. The shaft 20 is maintained in proper position within the bearing by means of a fibre spacer 22 disposed between the plate ll and the base l8 at the upper end of the shaft 20 and a nut and washer com- ,bination 23 at the lower end of the shaft.

Power to operate the motor I2 is supplied by way of a two-wire cord 24 and a suitable switch 25 secured to the base l8. A pair of collector rings 25, electrically connected with the switch 25 by a pair of conductors 21, are concentrically disposed in an insulating support 28 which, in turn, is received in a recess provided therefor in the base I8. Brushes 29 (Fig. 5), mounted in a holder 30 which is secured-to the plate H, cooperate with the rings 26 and supply power to the motor 12 and permit continuous rotation thereof. I i

In accordance with my invention, 1 provide novel means for oscillating theblower It, its motor l2 and the housing H) between variable limits, for rotating the same continuously at high or low speeds and which permits of stationary operation thereof, a manually operable control for such means also being provided. Further, the eonstruction'and arrangement is such that rotation or oscillation occurs in a plane always perpendicular to the vertical axis'of the fan, regardless of ,the degree'of. tilt at which the blower and the motor might be set, whereby air moved by the fan is always directed at the same angle with respect to the horizontal rather than being directed upwardly on one side and downwardly on the other side as the fan makes a complete revolution.

In carrying out my invention I employ a pinion 35 driven from the motor |2 and operatively associated with a pair of spaced, concentrically disposed,

circular racks

36 and 3| fixed in the base l8, and means operative to shift the pinion between the racks for oscillation or continuous ro v tational operation in either clockwise or counterclockwise directions. Provision is' also made to hold the pinion out of engagement with either of the racks for stationary operation. 7

A flexible driving connection with the-motor is utilized to drive the pinion 35. Thus, inthe which is adapted to engage either of the limit the shifting lever 4| into the position shown in Fig. 5 and the pinion 35 into mesh with the outer circular rack 31 thus causing rotation in a counterclockwise direction. Such movement of the shifting lever 44 also carries the arm 54 outward present instance, the rear end of motor shaft l4 has provided thereon a worm 38 which meshes with a worm wheel 39, the latter being journaled in. brackets 39a fixed to the motor casing I3. To provide flexibility to permit shifting of the pinion 35 between the racks 36 and 31, the worm wheel 39 is connected to the pinion by means of a flexible shaft 40. The pinion 35. is carried by a shifting lever 4|, by means of a bearing 43 fixed incthe shifting lever and disposed adjacent the pinion. The shifting lever 4| is pivotally supported intermediate its ends on a headscrew 42 fixed in the floor plate ll of the housing I9.

So that oscillation of the fan obtains, I provide means operatively' associated with the shifting lever 4| and responsive to limiting elements on the stationary base 8 to swing the lever 4| to shift the drive pinion 35 between the circular racks 36 and 31. To thisend, I utilize a second or tripping lever 44 and a spring 45. The tripping lever 44 is also pivotally mounted on the head screw 42 and is disposed in vertically spaced relation to the lever 4|, and the spring 45'is interposed between the twolevers 4| and 44. In the present instance the spring is of the so-called shutter type, operating as a compression spring, and has

legs

46 and 41 the ends of which are received in

openings

48 and 49 in the levers,4| and 44 respectively.

Movement of the tripping lever 44 in a counterclockwise direction from a position as shown in Figure 4 will cause the ends of the spring legs 46 and '4'! to be brought toward each other and therefore compress the spring. As the two ends of the spring are brought near each other, they become alined with the pivot 42, in a deadcenter relation and as movement in such direc tion continues the spring expands. Upon so doing, the end of the shifting lever 4| opposite the pinion is snapped inwardly, thus disengaging the pinion 35 from the inner circular rack 35 and causing it to be shifted over into engagement with the outer'rack 31. Since the rotation of the pinion 35 is unidirectional, such a shifting from engagement with the inner rack into engagement with the outer rack causes the fan to reverse its direction of rotation.

To determine the limits of the are through which oscillation of the fan occurs, I provide two concentrically disposed, peripherally arranged series of spaced

recesses

50 and 5| in the base I8 for the reception of

limit pins

52 and 53 respectively'and fashion the tripping lever 44 for cooperation with the pins. To this latter end, the tripping lever is provided with an outwardly extending arm 54, the outer end of which is bent downwardly so as to provide a depending dog 55- ly and thus positions the dog 55 over the outer series of recesses 5|. As rotation of the fan in a counterclockwise direction continues, the dog 55 is brought into engagement with the other limit pin 53, whereupon the tripping lever is again held back, i. e., forced in a clockwise direction about the pivot 42, and the snapping action is reversed causing the shifting of the lever 4| so as to disengage the pinion 35 from the outer rack 31, and shift it into engagement with the inner rack 35 thus producing rotation in a clockwise direction.

To prevent the

limit pins

52 and 53 from being set side by side which would prevent movement of the shifting lever 44 upon engagement of the dog 55 therewith, the pin 53 is provided with a flange 53a which is of sufiicient Width to partially overlie the recess adjacent that in which it is placed.

In use, it is desirable not only to have the fan oscillate but also to have it rotate continuously or to remain stationary. Thus I provide control means which is operative'to either-permit automatic oscillation of the fan as set forth above or to render the shifting mechanism ineffective and to provide manual control of the positioning of the drive pinion 35. To this end, I employ a lever 60 pivoted on'a head screw 32 in the plate I and having a cam slot 6| therein within which is received the pinion bearing 43. The contour of the cam slot 6| is fashioned so as to produce a bodily shifting of the pinion 35 in response to the movement of the lever 60 by meansof a finger piece 59 projecting outwardly therefrom or to permit shifting of the pinion automatically by the shifting mechanism. Thus one portion 6|q. of the cam slot is of sufficient width to permit movement of the pinion between the two circular racks 35 and 31 upon operation of the shifting mechanism as hereinbefore described. This wide slot portion 6|a comprises the right hand or lower end of the slot 3| as shown in Figs. 4 and 5. The remainder of the slot is of just sufficient width to permit movement of the pinion bearing 43 therein as the control lever 50 is moved about its pivot 62 and thus is effective to disable theshifting mechanism when the pinion bearing is positioned in such slot portion.

' As shown in Figs. 6 and '7, the control lever has been moved to dispose the bearing 43 in a position 6|b of the cam slot 6| and thus engage the pinion 35 with the outer circular rack 31 so that continuous operation in acounterclockwise direction obtains. If it is desired to rotate the fan at a higher speed, the control lever can be moved in acounterclockwise direction about the pivot 62 carrying the bearing further along the camslot into a position 6|c and thus engage the pinion with the inner circular rack 36, such higher speed being caused by the smaller speed reduction ratio between the pinion 35 and themher rack 36 as compared to the ratio between the pinion and the outer circular rack 31. I

For stationary operation of the fan, the control lever 55 is moved to position the pinion bearing in the end (Std of the cam slot (Fig. 8). In-such position the pinion 35 is held out of engagement withboth of the two circular racks 35 and 31 and thus, while it continues to be driven from the motor I2, its teeth engage nothing and therefore no rotational movement of the fan is produced.

To prevent any wandering of the fan from a stationary position that might be caused by vibration or the like, I provide a braking device which, as shown, comprises a cylindrical member 63, preferably of resilient material, depending from the control lever 50 in such a position that when the pinion is disposed in the end 61d of the cam slot 6|, the braking device is brought to bear against the inner surface 35a of the inner circular rack 36. Thus it is operative to maintain the fan in the position desired. It will be apparent to one skilled in the art that the braking device is by no means limited by the specific form just described but also includes a finger depending from the lower end of the lever 60 and engageable with the teeth of the rack 35 or any similar device providing braking between the rotating components and the stationary base when the control lever 50 is moved into neutral or stationary operation position.

To limit the amount of movement of the tripping lever 44 as it is shifted between its various positions, I provide means including a plurality of stop elements which are operative either to maintain the dog 55 in positions over the

recesses

50 and 5| or to permit movement of the tripping lever so as to clear the dog from such positions completely. Referring particularly to Fig. 4, wherein the control lever 50 is set for oscillating operation the tripping lever 41 is shown in the position assumed just after having been cammed inwardly by engagement of the dog 55 with the pin 53. Further movement of the tripping lever 44 in such direction, that might be produced by the action of the snap spring 45, is prevented so that the dog is maintained over the recesses 50 by engagement of a stop pin 65 carried by the lever 44 with the edge of control lever 50. ing dog 55 on the arm 54 of the tripping lever 44 is maintained in a position so that it will engage the pin 52 when the limit of the arc of oscillation determined thereby has been reached.

In Fig. 5, the tripping lever is shown in the position assumed during counterclockwise movement in oscillating condition of operation after having been cammed outwardly by engagement of the dog 55 with the pin 52. Further outward movement of the arm 54 of the tripping lever '44 is prevented by means of an inwardly extending finger 66, made integral with the tripping lever 44, engageable with a stop pin 61 fixed in the floor plate ll. Thus, the dog 55 is positioned to engage the limit pin 53'when the end of the oscillation arc is reached.

For continuously rotating operation, the tripping lever is permitted to move inwardly far enough so'that the dog 55 is cleared from disposition over the rows of

recesses

50 and 5|. Thus the control lever 60 is shaped so that when it lsset in positions other than'that foroscillating operation the stop pin 65 will not come-into Thus, the dependengagement therewith in order to permit further inward movement of the lever 44 For slow counterclockwise continuous rotation, movement of the tripping lever 44 is limited by engagement of the finger 65 with the support for the brake member 53 (Fig. 7). For fast clockwise rotation and stationary operation, movement of the tripping lever 44 is limited by engagement of the finger 66 with the controllever pivot 52, n

Should the tripping lever 44 be in the position shown in Fig. 5, in which the dog 55 is in its outermost position with movement of the fan occurring ina counterclockwise direction, and the control lever 50 be moved into one of its other positions as, for example, that shown in Fig. 6 to produce continuous counterclockwise rotation, upon engagement of the dog 55 with the pin 53, the tripping lever 44 will be shifted by'action of the'snap spring 45 into the position shown in Fig. 7, thus permitting continuous counterclockwise rotation to be obtained without interference by the oscillating mechanism.

Means is also provided to assist in getting the dog 55 from its positions over the rows of

recesses

50 and 5| when the control lever 60 is shifted from oscillating position into other positions thereof, and to get the dog back into position over the rows of recesses again when the control lever is returned to its setting for oscillating operation. Shifting of the control lever from the setting for oscillating operation moves the drive pinion 35 into engagement with the inner circular rack 36, and the outer end of the shifting lever 4| is correspondingly moved outwardly carrying with it the end 46 of the snap spring 45 aflixed thereto. To reduce the amount of movement necessary to reach a dead-center position between the ends of the

spring legs

45 and 41 and the pivot 42, 'I provide an upwardly projecting pin 68, fixed in the tripping lever 44, which is engageable with a cam lobe 69 adjacent the upper end of the control lever 50. Thus, as the control lever is moved in a counterclockwise direction the tripping lever 44 is cammed in a clockwise direction about its pivot 42 simultaneously with the movement of the shifting lever 4|. Thepivot 42 and the ends of the legs 46 and 4'! of the snap spring 45 are thus quickly brought into and through dead center position, whereupon the spring 45 will snap the tripping lever 44 into a position as shown in Fig. 7 and the lug 55 from disposition over the rows of

recesses

50 and 5|.

To return the dog 55 into a position for engagement with the

pins

52 and 53 from a position as illustrated in Fig. 8 wherein the control lever 63 is set for stationary operation of the fan, the lever 50- is moved in a clockwise direction about its pivot 52. Such movement causes the support for the brake member 53 to engage the finger B5 of the tripping lever 44 and rotates the la ter in a counterclockwise direction through the position shown in Fig. 7. As such movement is continued the cam lobe 69 engages the stop pin 65 and continues the counterclockwise rotation of the tripping lever 44 which compresses the snap spring 45 until the ends of the

spring legs

45 and 41 and the pivot 42 pass dead-center relation, whereupon the spring 45 expands and snaps the tripping lever 44 outwardly carrying the dog 55 into the position shown in Fig. 6.

In accordance with one feature of my invention the novel arrangement is such that the fan may be tilted to direct air always at a constant angle with 're'spect'to its'support, i. e., for any desired 7 degree of tilt at which the fan might be set, air moved by the fan will not be blown upwardly on one side of the circle of rotation and downwardly on the other side, but instead will always be blown at the same angle. To this end the motor 12 is pivotally mounted at 10 on a bracket H which as shown is integrally formed with and bent upwardly from the housing 'floor plate II. The pivot 10 permits tilting of the blower Hi, the guard cage l1, and the motor l2 with respect to the housing 10. Such tilting is accomplished by means of a bifurcated member 12 the ends of the legs of which are pivotally secured to the motor casing 13 at 13 and 14. The bight portion of the member 72 is fixed to one end of an adjusting screw 15 the other end of which extends through the housing H) where it is received in'a wing nut 16. By means of the latter, cooperating with the housing 10, the adjusting screw 15 can be axially shifted until the desired degree of tilt obtains, the vertically elongated slot !5 permitting the resulting movement of the motor shaft l4 and the guard cage mounting with respect to the housing 10. It is to be noted especially that the flexible driving connection between the motor l2 and the pinion 35, i. e., the flexible shaft 40 in the present instance, permits such tilting completely independently of the rotating and oscillating mechanism which at all times operates in planes fixed with respect to the base 18 and stand [9. Thus rotation and oscillation always occur in a horizontal plane regardless of the tilt setting of the fan.

From the foregoing therefore it can be seen that a fan embodying an oscillating mechanism constructed in accordance with the present invention permits the fan to be oscillated, rotated continuously, or held stationary; permits of oscillation through an arc of variable limits; permits change of condition of operation at any time regardless of the position of the fan at such time; and permits operation of the fan so as to direct air moved thereby always at a constant angle.

I claim as my invention:

1. In a fan having a stationary base, a housing rotatably mounted on said base and a motor supported within said housing and rotatable therewith, an oscillating mechanism comprising, in combination, a pair of circular racks concentrically disposed on said base, a pinion driven by said motor, a shifting lever pivotally mounted on said housing and rotatably supporting said pinion, and means automatically operable to swing said lever between alternativepositions to mesh said pinion with either of said racks, for rotating said housing and motor with respect to said base, said means including a tripping lever pivotally supported on said housing, a snap spring interposed between said shifting lever and said tripping lever, and limit elements on said base determining an arc of oscillation and engageable by said tripping lever to pivot the same and compress the spring until a dead center relation is passed so that said spring becomes operative to swing said shifting lever.

2, In a fan having a stationary base, a housing rotatably mounted on said base and a motor supported within said housing and rotatable therewith, an oscillating mechanism comprising, in combination, a pair of circular racks concentrically disposed on said base, a pinion driven by said motor, a shifting lever pivotally mounted on said housing and rotatably supporting said pinion, means automatically operable to swing said lever between alternative positions to mesh said 8 pinion with either of said racks for rotating said housing and motor with respect to said base, and a control member for said means movable into a plurality of positions and operative in one of said positions to permit automobile operation of said means and operative in its other positions to render said means inefiective and provide manual shifting of said pinion.

3. In a fan having a stationary base, a housing rotatably mounted on said base and a motor supported within said housing and rotatable therewith, an oscillating mechanism comprising, in combination, a pair of circular racks concentrically disposed on said base, a pinion driven by said motor, a shifting lever pivotally mounted on said housing and rotatably supporting said pinion, means automatically operable to swing said lever between alternative positions to mesh said pinion with either of saidracks, for rotating said housing and motor with respect to said base, and a control member for said means movable into a plurality of positions, said control member being operative inone of said positions to render said means inefiective and maintain said pinion out of engagement with both of said racks so that stationary operation of the fan obtains. 4. In a fan having a stationary base, a housing iotatably mounted on said base and a motor supported within said housing and rotatable therewith, an oscillatingmechanism comprising, in combination, apair of circular racks concentrically disposed on said base, a pinion driven by said motor, a shifting lever pivotally mounted on said housing and 'rotatably supporting said pinion, means'automatically operable to swing said lever between alternative positions to mesh said pinion with either of said racks, for rotating said housing and motor with respect to said base, and a control'member for said means supported on said housing for movement into a'plur'ality of positions and having a brake element thereon, said control member being operative in one of said positions to render said means ineffective and maintain said pinion out of engagement with both of 'said'racks, and in said'one position to bringtsaid brake element to bear against one of said racks "whereby stationary operation of the fan obtains.

5. In a fan having a stationary base, a housing rotatably mounted on said base and a motor supported within said housing and rotatable therewith, an oscillating mechanism comprising,

in combination, a pair of circular racks concentrically disposed on said base, a pinion disposed between said racks, a shaft drivingly connecting said pinion and,,said motor and journaled'in a bearing adjacent said pinion, a 'shifting leverpivotally mounted on said housing and supporting said bearing and pinion, and 'means automatically operable to swing said lever between alternative positions tomesh said pinion with either of said'racks for rotating said housing and motor with respect to said base, and a manually operable control lever pivotally supported on said housing for movement into a plurality of positions and having a'cam slot therein for-the reception of said bearing, said cam slot being fashioned to permit automatic operation of said means in one of said lever positions and in the other lever positions to prevent automatic operation and to provide manual shifting of said pinion,

6. In a fan having a motor and a housing enclosing said motor'and providing a'fioor plate, an ioscillating mechanism comprising, in combination, a stationary base having series of spaced recesses therein, a pair of limit pins disposed in two of said recesses and defining an arc of oscillation, a pair of circular racks concentrically disposed on said base, a pinion unidirectionally driven by said motor and engageable with either of said racks to rotate the fan, a shifting lever pivotally mounted intermediate its ends on said floor plate and supporting said pinion on one end thereof, a tripping lever pivotally mounted on said plate in vertically spaced relation to said shifting lever, a spring interposed between said tripping lever and the end of said shifting lever opposite said pinion, said spring being operative to move the shifting lever in response to movement of said tripping lever upon engagement of the latter with said limit pins so that said pinion is shifted into alternative positions for engagement with either of said racks whereby oscillation of the fan obtains.

7. A fan comprising, in combination, a stationary base, a housing rotatably mounted on said base and having a vertically elongated slot therein, a motor pivoted within and rotatable with said housing and having a shaft one end of which projects through said slot, a blower secured to said projecting shaft end and disposed outside of said housing, means operative to tilt the motor on its pivot with respect to said housing, said slot permitting the resulting movement of the motor shaft, a pair of circular racks concentrically secured on said base and disposed in a horizontal plane, a pinion disposed between said racks, a flexible driving connection between said motor shaft and said pinion, and means operative to shift said pinion into alternative positions for engagement with either of said racks so that the fan will be rotated, said flexible driving connection permitting the shifting of said pinion and tilting of the motor relative to said stationary base whereby the fan, when set at any desired angle of tilt, will direct air moved by it at such angle.

8. A fan comprising, in combination, a stationary base, a housing rotatably mounted on said base and having a slot therein, a motor pivotally mounted within said housing and rotatable therewith and having a casing and a shaft the ends of which extend beyond said casing with one of said ends projecting through said housing slot, a blower secured to said projecting shaft end and disposed outside of said housing, a worm rigid with the other of said shaft ends, a worm wheel supported on said motor casing and meshing with saidworm, a pair of stationary circular racks concentrically disposed on said base, a pinion disposed between said racks, a flexible shaft drivingly connecting said pinion and said worm wheel, means operative to shift said pinion into alternative positions for engagement with either of said racks for rotating the fan, and means operative to tilt the motor and the blower with respect to said housing and said base, said flexible shaft permitting such tilting with respect to said base independently of the rotation of the fan.

9. A fan comprising, in combination, a stationary base having a series of spaced recesses peripherally disposed therein, a housing rotatably mounted on said base, a motor within said housing and rotatable therewith, a blower driven by said motor, limit pins disposed in said recesses and determining an arc of oscillation, a pair of circular racks concentrically disposed on said base, a pinion driven by said motor and disposed between said racks, a shifting lever pivotally mounted on said housing and supporting said pinion, a tripping lever pivotally mounted on said housing and operatively associated with said shifting lever to swing the same for meshing said pinion alternately with either of said racks, said tripping lever having an arm rigid therewith fashioned to engage said limit pins for moving the tripping lever, a control member operatively associated with said pinion and shifting lever and movable into a plurality of positions, and means including a plurality of stop elements operative to maintain said arm in position for engagement with said limit pins when said control member is in one of its positions so that oscillating operation obtains and operative to permit said arm to swing clear of said pins when said control member is in other positions thereof so that continuous rotation of the fan obtains.

10. A fan comprising, in combination, a stationary base having a series of spaced recesses peripherally disposed therein, a housing rotatably mounted on said base, a motor within said housing and rotatable therewith, a blower driven by said motor, limit pins disposed in said recesses and determining an arc of oscillation, a pair of circular racks concentrically disposed on said base, a pinion driven by said motor and disposed between said racks, a shifting lever pivotally mounted on said housing and supporting said pinion, a tripping lever pivotally mounted on said housing and having an arm fashioned to engage said limit pins for moving the tripping lever, a spring interposed between said tripping lever and said shifting lever operative to swing the shifting lever in response to movement of said tripping lever, a control lever operatively associated with said pinion and movable into a plurality of positions, means including a plurality of stop elements operative to permit said arm to swing into a position clear of said limit pins when said control lever is in other positions thereof so that continuous rotation of the fan obtains, a pair of pins fixed in said tripping lever in spaced apart relation and in spaced relation to the tripping lever pivot, and a cam lobe on said control lever engageable alternately with said tripping lever pins to initiate movement of the tripping lever into and out of said clear position upon movement of said control lever.

KENNETH A. ELLIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 610,852 Rolle Sept. 13, 1898 1,316,907 McEwen Sept. 23, 1919