US2350383A - Pitch adjusting mechanism for propeller fans - Google Patents

Description

' June 6, 1944.

c. N. BEBINGER 2,350,383 PITCH ADJUSTING MECHANISM ron PROPELLER mus Filed July 5 1942 v 2 Sheets-Sheet 1 25 30 T 32 5 3mm y; mar/g; Nflefiz'izyer I5 23 43 35 36 14 $3M W I June 6, 1944. Q BEBlNGER 2,350,383

PITCH ADJUSTING MECHANISM FOR PROPELLER FANS Filed July 3, 1942 2 Sheets-Sheet 2 l 1 3b t I i I;

W m (M7188 M5951)? Patented June 6, 1944 PITCH ADJUSTING MECHANISM FOR PROPELLER FANS Charles N. Bebinger, New Philadelphia, Ohio, as-

signor to La-Del Conveyor & Manufacturing Company, New Philadelphia, Ohio, a corporation of Ohio Application July 3, 1942, Serial No. 449,609

6 Claims.

The invention relates generally to propeller type fans for moving air or fluids underpressure through ducts, and more particularly to simple mechanism for adjusting the pitch of the propeller blades within predetermined limits to vary the volume and pressure of the fluid flow.

Such propeller type fans are used for example as ventilating fans for mines, buildings and ships, and it is often desirable to vary the volume and pressure of the fluid flow to meet changing conditions, particularly in the case of ships, where the atmospheric and climatic conditions vary greatly as the ship proceeds on its course.

Certain prior mechanisms for adjusting the pitch of the propeller blades have included hub constructions requiring either dismantling the fan tail section or working from Within the inner fairing of the fan in order to adjust the pitch of the blades.

Other prior constructions have included adjusting means extending outwardly into or through the air stream. These latter constructions are necessarily complicated and create turbulence and friction losses in the air stream.

It is therefore a general object of the present invention to provide simple mechanism for adjusting the blade pitch without encountering the difliculties and experiencing the disadvantages of prior constructions.

Another and more specific object is to provide pitch adjusting means which can be operated easily by reaching through a door or opening at a convenient location in the outer duct of the fan.

A further object is to provide adjusting means accessible from the exterior of the inner fairing.

Another object is to provide adjusting mechanism for changing the blade pitch within predetermined limits merely by loosening screws accessible from the exterior of the inner fairing, and changing the pitch of all of the blades by manually twisting one blade.

A further object is to provide means for easily changing the range of adjustment provided by the normal adjusting means.

A still further object is to provide extremely simple and inexpensive pitch adjusting mechanism which can be operated quickly and easily without dismantling any part of the fan structure, and without requiring access to the interior of the inner fairing.

These and other objects are accomplished by the improvements, arrangements and combinations comprising the present invention, which is illustrated by way of example in the accompanying drawings, and which is hereinafter described and claimed.

In general terms the present invention may be set forth as including an adjusting member rotatable within the inner fairing connecting all of the propeller blade hubs and adjustably secured to the fairing by means of clamping screws passing through slots therein, said screws being accessible exteriorly of the inner fairing through a door or hatch in the outer duct, and a ring rotatable within certain limits between said adjusting member and said inner fairing for varying the range of adjustment by changing the length of the fairing slots through which the clamping screws pass.

Referring to the drawings in which a preferred embodiment of the invention is shown by way of example,

Figure 1 is a fragmentary longitudinal section through the outer duct of a propeller type ventilating fan, part of the inner fairing being broken away to show the propeller hub construction and the adjusting means for the blades;

Fig. 2 is an enlarged fragmentary section similar to Fig. 1 showing the connection between the adjusting member and a propeller blade shank and one of the clamping screws;

Fig. 3 is a fragmentary transverse sectional view as on line 3-3, Fig. 2;

Fig. 4 is a transverse sectional view through the inner fairing as on line 44, Fig. l; i

Fig. 5 is an enlarged fragmentary elevation as on line 55, Fig. 4;

Fig. 6 is an enlarged fragmentary elevation as on line fi8, Fig. 4;

Fig. 7 is an enlarged fragmentary view similar to Fig. 4 showing the position of one of the normal adjusting screws at one limit f pitch adjustment;

Fig. v8 is a similar viewv showing the position of said adjusting screw at the other limit of pitch I adjustment Fig. 9 is an enlarged fragmentary view similar .to Fig. 4 showing the position of one of the range adjusting screws for pitch adjustment between the limits shown in Figs. '7 and 8;

Fig. 10 is a view similar to Fig. 7 showing one limit of pitch adjustment for a different range;

. Fig. -11' is a view similar to Fig. 8 showing the other limit 'of pitch adjustment for the different range; and

Fig. 12 is a view similar to Fig. 9 showing the position of the range adjusting screw for pitch adjustment between the limits shown in Figs. 10 and 1 1.

Similar numerals refer to similar parts through the drawings.

The propeller ventilating fan to which the present invention is applied is normally of relatively large diameter, but it will be understood that theinvention may be applied to propeller type fans adapted for other uses, without departing from the scope of the appended claims.

As best shown in Figure 1, the fan includes an outer duct or fairing indicated generally at l3, preferably cylindrical as shown throughout that portion of the duct surrounding the nose I4, propeller blades l5 and straightener vanes l6. The outer duct is preferably made up of adjoining sheet metal sections as indicated at IT and I8,

which are secured together by suitable means such as flange rings 9 clamped together by bolts (not shown).

The outer duct is provided preferably opposite the nose I4 of the inner fairing with a door or hatch indicated at 26, which is adapted to be easily removed, or may b hinged in a suitable manner, and the inner surface of the door is flush with the inner surface of the outer duct so as to provide a smooth surface which will not interfere with the air flow through the duct.

The inner fairing preferably includes the hollow nose section l4, and a cylindrical housing section 2| which may enclose the motor; and the housing section 2| is preferably supported within the rear part of the nose so as to provide a smooth I streamlined air flow along the inner fairing.

The hub section 22 includes an annular rim 23 provided with a plurality of circumferentially spaced sockets 24 in which the shanks 25 of the propeller blades l5 are journaled, and a ribbed disk portion 21 connecting the sockets 24 to the propeller shaft hub 26. Th propeller shaft hub 26 is keyed on the motor shaft 28 by means of keys 29 in a usual fashion.

Preferably, the blades |5 are held in their sockets 24 by means of clamping collars 30 engirdling the shanks 25 and the collars may be of two parts clamped together tightly around the shank by bolts 3| (Fig. 4). A stud 32 projects radially from each collar '30,"theprojecting ends of the studs being rounded at 33, as best shown in Fig. 2.

Preferably, the rear end of the nose I4 is rabbeted as shown at 34 (Fig. 2), and a flange 35 on the rim 23 fits into the rabbeted portion to form a smooth joint between the nose and hub section, screws 35 being provided to secure the nose l4 and hub section 22 together.

Means for operatively connecting all of the propeller blades l5 so that changing the pitch of one will change the pitch of all of the blades a corresponding amount, preferably includes an adjusting member or spider 31 which is journaled at its central portion on the hub 26, as indicatedat 31'.

The adjusting spider 3'! is provided with'radially projecting portions 38 for connecting one with each propeller blade shank, and each projecting portion 38 has a slotted socket member 39 secured therein for receiving the rounded head 33 of one of the studs 32 projectin from each propeller blade shank. The socket members 39 are secured in the projecting portions 38 by means of nuts 40 screwed onto studs 4| provided on the socket members 39 and projecting through the portions 38 of the spider.

The rounded heads 33 of th studs 32 fitting in the socket members 39 allow the collars 32 to be rotated in one plane by rotation of the spider 31 in a plane perpendicular thereto, without requiring any clearance at the connection. Thus rotation of the spider 31 will cause the collars to shows one of the screws 46 axially rotate and simultaneously change the pitch of all of the blades 5.-

Preferably two diametrically opposite projecting portions 38 as indicated at 38a are extended radially outward to slidably abut a range adjust- I ing ring 42 which is adjustably secured for limited rotation on the inside of the rim 23 of the hub section. The projecting portions 38a are each rotatably adjustably secured to th rim 23 of the hub section by a screw 43 which passes radially through a circumferentially extending slot 44 in the rim 23 and through a circumferentially extending slot 45 in the ring 42 and is threaded into the portion 38a, the slots 45 being adapted to register with slots 44. Thus by loosening th screws 43, the spider member 31 can be rotated in opposite directions relative to the rim 23 by amounts determined by abutment of the screws 43 with the ends of the slots.

The ring 42 is adjustbly secured for limited rotation on the rim flange 23 by means of two other screws 46 located preferably at from the screws 43, said screws passing radially through circumferentially extending slots 41 in the rim flange 23 and being threaded through the ring 42. Preferably the screws 46 have stop nuts 48 screwed on their inner ends to prevent removal of the screws. Thus by loosening the screws, the ring 42 can be rotated in opposite directions on the rim flange23 by amounts determined by abutment of the screw 46 with the slots 41.

In the normal operation of the fan, when it is desired to adjust the pitch of the blades, the operator stops the fan and opens the door 20 in the outer duct l3. He then reaches in with a suitable tool to loosen first one screw 43 and then the other screw 43 by manually turning the propeller to bring the screws into accessible position. Then by grasping one of the blades. l5

andtwisting it to the desired pitch, the pitch of all of the blades is automatically adjusted. It is not necessary to loosen screws 46 for this normal adjustment.

As shown in Figs. 4 and 6, the screws the middle position of adjustment, and the position L at one limit designates a blade pitch giving about less volume and pressure delivered by the fan than the blade pitch designate-slat the position H. I

As shown in Figs. 4 and 5, the range adjusting screws 46 are in their middle position of adjustment, and the position +10 at one limit increases the adjustment range in volume and pressure by 10% over the volume and pressure at position 0. These screws are set at the desired position, as by a superior olficer on a ship, for giving a certain adjustment range based on atmospheric and climatic conditions, and the blade pitch is adjusted from} time to time by a mechanic charged with the duty of adjusting the blade pitch by manipulating the screws 43. If the ship is to be cruising for a time in a location having conditions requiring a different range of adjustment, the superior officer may adjust the range by first loosening screws 43 and then screws 46, whereupon by twist ng one of the blades l5 the ring 42 may be rotated relative to the rim to the desired position.

Referring to Figs. '7 to 12 inclusive, Fig. 9

adjusted to 0 position and Figs. 7 and 8 show the range of adjustment determined by screws 43 with the range adjusting screws at 0 position. Thus with screws 46 fixed at 0 position the pitch can be adjusted 43 are in from L position shown in Fig. '7, where screw 43 abuts one end of slot 45 in ring 62, to H position shown in Fig. 8 giving more volume and pressure, in which screw 43 abuts the other end of slot 45.

Fig. 12 shows one of the screws 46 adjusted to +10 position to increase the range in volume and pressure by 10%, in which position the screw 46 abuts the other end of slot 4'! in rim 23. Figs. 10 and 11 correspond to this new position and show the slot 45 in ring moved clockwise relative to rim 23. Thus with screws 46 fixed at +10 position, the pitch can be adjusted from a new L position shown in Fig. 10 giving 10% more volume and pressure than the L position in Fig. '7 to a new H position shown in Fig. 11 giving 10% more volume and pressure than the H position in Fig. 8.

Obviously the screws 4t may be fixed in positions intermediate the and positions to change the adjustment range by varying amounts.

The improved pitch adjusting mechanism is extremely simple and inexpensive, and can be operated with ordinary tools and without dismantling or requiring access to the interior of the inner fairing. Moreover, none of the adjusting mechanism extends into the air stream to disturb the fluid flow.

Normal adjustment of the blade pitch is accomplished merely by reaching through the door in the outer duct and loosening the two screws 43, while the adjustment range can be varied by reaching through the same door and loosening the two additional screws 46.

I claim:

1. In a propeller type fan located within an outer duct having a door therein, and having an inner fairing formed in part by the outer rim of a hub section, and a plurality of propeller blades mounted in and projecting radially from said hub section, pitch adjusting mechanism accessible exteriorly of said inner fairing through said door, said pitch adjusting mechanism including an adjusting member rotatable within said hub section, means operatively connecting said adjusting member to all of the blades whereby rotation of said adjusting member varies the pitch of said blades, means adjustably securing said adjusting member to said hub section outer rim for rotatable adjustment within a predetermined range, a ring located between said adjusting member and said hub section outer rim for varying the range of rotation of said adjusting member, and means rotatably adjustably securing said ring to said hub section outer rim.

2. In a propeller type fan located within an outer cylindrical duct having a door therein, and having a smooth streamlined inner fairing formed in part by the outer rim of a hub section, and a plurality of propeller blades mounted in and projecting radially from said hub section, pitch adjusting mechanism accessible exteriorly of said inner fairing through said door, said pitch adjusting mechanism including an adjusting member rotatable within said hub section, means operatively connecting said adjusting member to all of the blades whereby rotation of said adjusting member varies the pitch of said blades, and means rotatably adjustably securing said adjusting member to said hub section outer rim for movement within definite limits and accessible exteriorly of said outer rim.

3. In a propeller type fan located within an outer duct having a door therein, and having an inner fairing formed in part by the outer rim of a hub section, and a plurality of propeller blades mounted in and projecting radially from said hub section outer rim, pitch adjusting mechanism accessible exteriorly of said inner fairing through said door, said pitch adjusting mechanism including an adjusting member rotatable within said hub section, means operatively connecting said adjusting member to all of the blades whereby rotation of said adjusting member varies the pitch of said blades, a screw in said adjusting member extending through a slot in said hub section outer rim for securing said adjusting member for rotatable adjustment within the limits of said slot, a ring located between said adjusting member and said outer rim and having a slot through which said screw extends, and means rotatably adjustably securing said ring to said outer rim.

4. Pitch adjusting mechanism for a propeller fan having a hub and a plurality of blades projecting radially from the outer rim thereof, including an adjusting member rotatably mounted in the hub, means operatively connecting the blades to said adjusting member for varying the pitch of all of the blades, a ring located between said adjusting member and said hub outer rim, means extending radially through the hub outer rim and ring and. securing said adjusting member to said outer rim for limited rotatable adjustment relative to said outer rim, and means extending through said hub outer rim and securing said ring to said outer rim for limited rotatable adjustment relative to said outer rim.

5. Pitch adjusting mechanism for a propeller fan having a hub and a plurality of blades projecting radially from the outer rim thereof, said outer rim having spaced circumferential slots therethrough, including an adjusting spider journaled in the hub for rotation axially thereof, means operatively connecting the blades to said spider f or varying the pitch of all the blades when the spider rotates, a range adjusting ring located between said spider and said outer rim and having a circumferential slot adapted to register with a $101; in the outer rim, a screw secured in said spider and extending through said registering rim and ring slots for securing said spider to said rim for rotatable adjustment of the spider within the limits of said registering slots, and a second screw secured to said ring and extending through another of the slots in said outer rim for rotatably adjustably securing the ring to said rim.

6. In a propeller fan including a hub section having an outer rim forming .part of the inner fairing, a plurality of propeller blades projecting from said rim and having their shanks journaled in said hub outer rim, a spider journaled in the hub for rotation axially thereof and having sockets one for each blade, a clamp secured to each blade shank, round headed studs projecting one for each clamp received in said sockets providing a connection between the blades and the spider for changing the pitch of all the blades by rotation of the spider, means adjustably securing said spider to said hub outer rim for limited relative rotatable adjustment of the spider, a range adjusting ring between said spider and said outer rim for varying the range of adjustment of said spider, and means rotatably adjustably securing said ring to said outer rim.

CHARLES N. BEBINGER.

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