US2450420A

US2450420A - Variable pitch impeller

Info

Publication number: US2450420A
Application number: US696970A
Authority: US
Inventors: Cranmore W Cline
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-09-13
Filing date: 1946-09-13
Publication date: 1948-10-05
Anticipated expiration: 1965-10-05

Description

' Oct. 5; 1948. c. w. CLINE 2,450,420

VARIABLE PITCH IMPELLER Filed Sept. 15, 1946 3 Sheets-Sheet 1 Fig.

75 INVENTOR. 79 73% "-74 M72 G/PA/VMORE m GLl/VE v 1T] BY I \/7 88 ATTORNEY Oct. 5, 1948. c. w. CLINE I 2,450,420

-VARIABLE PITCH IMPELLER Filed Sept. 13, 1946 3 Sheets-Sheet 2 w INVENTOR.

GRAN/"ORE W ULl/VE ATTORNEY Oct. 5, 1948. c. w. CLINE VARIABLE PITCH IMPELLER 3 Sheets-Sheet 3 Filed Sept. 15, 1946 Fig.5

' FLY MM W M m M. m

A T TORNE Y Patented Oct. 5, 1948 UNITED STATES PATENT OFFICE VARIABLE PITCH IMPELLER Cranmore W. Cline, United States Navy,

Jacksonville, Fla.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 2 Claims.

This invention relates to variable pitch impellers and more particularly to mechanisms for adjusting the pitch of the same.

An object of the invention is to provide an improved impeller of simple construction and adapted to have its pitch adjusted while in operation.

Other objects of the invention are to provide an improved variable pitch impeller for driving the reel of an aircraft tow target at different rates of speed; to provide an improved impeller, of the character described, having actuating means operable by the rotation of the impeller; to provide an improved mechanism for adjusting the pitch of an impeller during rotation of the same; to provide a control for the manual operation of the pitch of the blades on the impeller; to provide a control for utilizing, at the will of the operator, the impeller drive shaft as a source of power for the changing of the pitch of the impeller blades, in such a direction that will cause the impeller to stop rotating; to provide an improved impeller mechanism, of the character described, wherein the control means has connection with the impeller blades and with the drive shaft of said impeller and includes means for utilizing the rotation of said drive shaft to impart oscillation to said blades about their respective axes so as to vary the pitch of the same; and to provide improved elements and arrangements thereof in an impeller mechanism of the character described and for the purpose set forth.

In accomplishing these and other objects of the present invention, I have provided improved details of structure, the preferred form of which is illustrated in the accompanying drawings, wherein:

Fig. 1 is a transverse, vertical, sectional View of a portion of an aircraft fuselage having an impeller and control mechanism embodying the features of the present invention mounted thereon and therein and shown connected to a tow target reel. I

Fig. 2 is a longitudinal, sectional view of the impeller.

Fig. 3 is a cross-sectional view, taken on the line 33 of Fig. 2.

Fig. 4 is an isometric view of a portion of the traversing mechanism, showing its relation to the drive shaft of the impeller.

Fig. 5 is a cross-sectional view, taken on the line 5-5 of Fig. 2, showing the connection between the impeller and the flexible cable which extends to the control mechanism.

Fig. 6 is a detailed sectional view of the control mechanism, taken on the line 6-6 of Fig. 1.

Fig. 7 is a cross-sectional view of the control mechanism, taken on the line 'l! of Fig. 6.

Referring more in detail to the drawings:

In Fig. 1, the numeral I0 designates a portion of the fuselage of an aircraft, such as an airplane, having an impeller l I mounted thereon for driving a tow target reel l2, or other means, which is mounted in a suitable frame 13. A driven shaft l4, coupling l5, and gear box l6 operatively connect the impeller H to the reel l2, the gear box permitting selective engagement and disengagement of said reel relative to the shaft and its coupling. As will be hereinafter more fully explained, the pitch of the impeller is adapted to be varied by a control mechanism I! which is operatively connected to the gear box IE by a flexible drive shaft or cable l8 and to said impeller by a second flexible drive shaft or cable l9. e

The impeller ll includes an upright mounting support or standard 20 upon which a cylindrical nacelle or shell 2i (Fig. 2) is mounted in sub-- stantially parallel relation to the fuselage (Fig. 1).

As shown in Fig. 2, a cylindrical bearing housing or collar 22 is disposed concentrically within the forward portion of the shell 2! and has an external, radial flange 23 adjacent its forward end, which flange overlies the forward open end of said shell and is secured thereto by suitable stud bolts 24 and nuts 25. The innermost end of the bearing housing 22 is of reduced diameter and is provided with an internal, radial flange 26 to form an annular recess or socket 21 for receiving a ball bearing assembly 28. An axial drive shaft 29, having the bearing assembly 28 confined upon the inner end portion thereof, extends through the bearing housing 22 and projects forwardly thereof. The rear extremity of the shaft 29 carries a bevelled pinion 30 which has its teeth in constant mesh with the teeth of a complementary pinion 3| mounted on the upper end of the driven shaft M, the latter extending into the shell 2i and being journalled therein by a ball bearing assembly 32.

A hub 33, having an axial bore 34, is keyed or" radial sockets 36 (Fig. 3) which are preferably equally-spaced and have been illustrated as being four in number.

Each socket 36 is adapted to receive the shank or root of a blade 31 and is progressively enlarged or stepped outwardly to provide a plurality of counterbored or shouldered portions. Each blade 3? has its shank formed complementary to its socket and carries in scquential order a small ball bearing assembly 38, a spur gear 39, Fig. 2, a lock nut 40 and a large ball bearing assembly 4| which engage within the counterbored portions of said socket. A housing or casing 42 encloses the hub and includes a nose or cap section 43 and coacting annular cages or

sections

44 and 55, the latter encircling said hub and rotatably confining the blades shanks within their sockets.

As shown in Figs. 2 and 3, the hub 33 is formed with a plurality of longitudinal ports or keyways 46 intermediate and extending at right angles to the sockets 36, with each keyhole communicating with the adjacent counterclockwise socket. A reciprocable bar or rod 41, having a gear rack 48 secured thereto, is, slidably mounted in each keyhole 46 and projects rearwardly therethrough. The teeth of each gear rack 48 are in constant mesh with the teeth of the adjacent counterclockwise spur gear 39, whereby the blade upon which said gear is mounted is oscillated about its axis by reciprocation of the rod 47 carrying said rack. In effect, the rods and gear racks form a part of the control mechanism H and are adapted to be simultaneousl and uniformly reciprocated by means of an actuating or connecting member 49 which is slidably confined upon the drive shaft 29 rearwardly of the hub.

As is most clearly shown in Fig. 4, the member 49 includes a radial flange 50 and a plurality of equally-spaced, rearWardly-directed fingers which are arcuate in cross-section and snugly engage the peripheral surface of the shaft 29 (Fig. 2). Keyholes 52 are formed in the flange 59 of the connecting member for receiving the-rearward k ends of the rods 41 and connecting the same to said member. lJhe fingers 5| extend longitudinally between radial ribs or lugs 53 formed on the shaft 29 and have their rearward or free ends reduced in thickness for receiving an annular, splined spacer 54 and a pair of annular nuts or rings 55 which are screw-threaded upon said fingers ends and confine the spacer thereupon with its splines between said fingers. Due to the relation of the fingers and the lugs 53, the member 49 rotates with the drive shaft and is slidable longitudinally thereof. For receiving an annular, rearwardly-directed bearing collar 56 formed on the hub 33 (Fig. 2), the inner, forward portions of the fingers are recessed as shown by the numeral 51 (Fig. 4).

A ball bearing assembly 58 is mounted within the bearing housing 22, Fig. 2, forwardly of its flange 23 and in surrounding relation to the fingers 5|, for centering the connecting member 49 within said housing and permitting relative rotation and reciprocation of said member. In order to reciprocate the connecting member, a pair of annular, traversing elements or guides 59 and 69 are disposed within the rearward portion of the bearing housing 22 concentrically of the drive shaft 29. The outer or female guide 59 is fixed against rotation within the bearing housing by suitable means, such as splines or keys 6|, and is internally recessed to receive a ball bearing assembly 62 which is confined upon the rearward ends of the fingers 5| of the connecting member.

by the nuts 55. An annular bearing cap 63 connects the female guide to the bearing assembly 62, whereby reciprocation of said guide is tran$- mitted to the member 49 without interfering with the rotation of said member. Forward reciprocation of the member is limited by a spacer ring 64 which encircles the fingers of the connecting member forwardly of the bearing assembly 62 and which is adapted to engage the bearing assembly 58 upon such reciprocation.

The inner or male guide is screw-threaded within the outer, non-rotatable guide 59 and is rotatably supported by an annular bearing member 65 which is secured to the bearing housing 22. immediately forward of its recess 21. An internal, annular flange portion 66 projects rearwardly from the guide 60 and is rotatably confined upon the bearing member 65 b a coacting radial flange or shoulder 61 formed internally of and at the forward end of said bearing member. For imparting rotation to the inner guide 60 so as to reciprocate the outer guide 59, the flange portion 66 of said inner guide has a worm gear 68 secured externally thereon. A suitable thrust bearing 69 encircles the flange portion and bearing member rearwardly of the worm gear 68.

As is clearly shown in Fig. 5, a worm 70 has its teeth in constant mesh with the teeth of the worm gear 68. The worm 19 is carried by a short shaft H which is journaled in the bearing housing 22 and extends through the wall of the shell 2| into the standard 20 (Fig. 2), being suitably coupled to the flexible shaft l9. By virtue of the foregoing arrangement, rotation of the flexible shaft I9 is transmitted through shaft H, worm 10 and worm gear 68 to the inner traversing guide 6|]. Since the outer traversing guide 59 is keyed against rotation, rotation of the inner member causes sliding movement of said outer member. This movement is imparted through the bearing assembly 62, actuating member 49, and rods 4! to the gear racks 48 so as to oscillate the spur gears 39 and the blades 31 about their respective axes during rotation of the hub 33 and said blades about the longitudinal axis of the shaft 29.

Rotation of the flexible shaft I9 is affected by means of the control mechanism l1. As shown in Figs. 1, 6 and 7, the mechanism includes a rectangular housing or casing 12 mounted on the frame l3 and having a pair of parallel shafts 13 and I4 journaled therein. The flexible shafts I8 and [9 are connected to the shafts l3 and 14, respectively, which shafts have drums or

rollers

15 and 16 mounted thereon, whereby said shaft 13 and its roller 15 are constantly driven by said flexible shaft l8. .An idler assembly 11 is disposed Within the casing I2 for operativel connecting the rollers 15 and I6 and includes a spring-pressed yoke member '18 having its parallel legs or arms extending at right angles to said rollers between the shafts 13 and I4. The yoke member l8 rotatably supports an idler drum or roller 19, by means of a suitable shaft 89, which roller is parallel to and adapted to be engaged with the

rollers

15 and 16 upon movement of said yoke member in a plane transverse to the longitudinal axes of said latter rollers.

A cam element 8| is pivotally supported externally of the casing 12, between suitable lugs or cars 82, in engagement with a pin or button 83 carried by the yoke member and extending through an opening in said casing, whereby pivoting of the cam element in a counter-clockwise direction causes inward reciprocation of said yoke member and engagement of its idler roller with the

rollers

15 and 16. The button 83 is held in engagement with the cam element 8| by a, coiled spring 84 which is confined between an annular boss 85 formed internally of the easing and a co-axial pin 86 carried by the yoke member opposite said button. Displacement of the yoke member is prevented by the engagement of the button in the casing opening and the action of the pin 85 with the annular boss 85. A U-shaped guide element or bracket 31 is mounted internally of the casing in engagement with the yoke member for preventing turning or pivoting of said member about the axes of its button and pin. Upon engagement of the rollers, rotation is imparted to the roller 16, shaft M, flexible shaft I9, shaft ll, Fig. 5, and worm "l0 so as to drive the worm gear 68 and thereby turn the blades 31 about their respective axes, as explained hereinbefore. It is pointed out that one end of the shaft l4 ext-ends entirely through the casing and has a hand wheel 88, Fig. 6, mounted on it projecting end to permit manual oscillation of the blades and adjusting of the pitch thereof.

Operation The operation of a variable pitch impeller and control mechanism therefor, constructed as described, is as follows:

During take-offs and landings, the blades 3? of the impeller are full feathered to offer as little wind resistance as possible. The feathering of the blades is accomplished manually, by means of the hand wheel 88 upon take-oifs and either manually or mechanically by pivoting the cam element 8 i upon landings.

When it is desired to rewind the tow target reel 12, the driven shaft I4 is operatively connected to said reel by manipulation of the gear box It. Since the shaft i4 is driven by its connection with the drive shaft 29, rotation of the impeller blades and their hub 33 is transmitted to the reel. Although rapid rewind is desirable, it is essential to control the speed of rotation of the impeller to prevent overspeeding of the same. The load imposed on the impeller is constantly reduced by reeling in of the cable with the result that the speed of said impeller is increased. By increasing the pitch of the impeller blades, the rotational speed of the same is decreased and the rate of rewind reduced. This control is important during completion of the rewind and permits inching in of a target sleeve (not shown).

In order to feather or decrease the pitch of the impeller blades, the cam element is! is swung in a counter-clockwise direction so as to move the idler assembly i1 inwardly or to the right (Figs. 6 and '7) and move its roller i9 into engagement with the rollers 15 and i6. Since the roller i is rotated by the connection of its shaft 13 to the flexible shaft 18, in turn driven by its connection with the gear box it, the roller l8 and its shaft 14 are rotated by the aforesaid engagement of the rollers. This rotation is imparted to the inner traversing member 68 through the flexible shaft l 9, shaft 1 i, worm if! and worm gear 68 (Figs. 2 and 5).

Due to the provision of the keys BI and the screw-threaded connection between the traversing guides, the outer traversing guide 59 is slid outwardly longitudinally of the shaft 29 by rotation of the guide BE. The bearing assembly 62 and cap 63 impart similar longitudinal movement to the actuating member at so as to reciprocate the rods 4? and their gear racks 48 forwardly, thereby turning the spur gears 39 and the blades 31, upon which said gears are mounted, about their respective axes. In this manner, the

- departing from the spirit of the invention.

6 pitch of the blades is increased so as to decrease the rotational speed of the same and thereby reduce the rate of rewind of the reel l2.

Full feathering of the blades is accomplished by continued actuation of the control mechanism H which moves the racks l8, rods ll, member 49, bearing assembly 62, cap 63 and guide 59 outwardly until the spacer ring 64 engages the bearing assembly 58. It is pointed out that actuation of the control mechanism continues so long as the cam element 8i maintains the idler assembly 17 inwardly of the casing l2 with its roller 19 in engagement with the roller '15 and 76. Upon release of the cam element, the compression of the spring 84 urges the assembly outwardly or to the left (Figs. 6 and 7) so as to disengage the rollers and thereby render the control mechanism inoperative. Due to the construction of the impeller, the blades thereof will retain the pitch to which the same have been adjusted at the moment of disengagement of the rollers and nonoperation of the control mechanism.

As has been explained, the pitch of the impeller blades may be varied manually, at will, by the provision of the direct connected shaft l9 between the operator and the pitch changing mechanism, manually controlled by the hand wheel 88. Of the three rubber covered rollers in the control box, two of these rollers are respectively connected to the flexible shafts. One of the drive shafts goes to the pitch changing device and the other one goes to the impeller main power drive shaft. The third and last rubber covered roller is merely an idler and is there to provide a means of coupling, at will, the two other before mentioned rollers. When the two rollers that are connected to the flexible drive shafts are coupled together, by means of the idler roller, the following result is obtained. The roller that is driven by the impeller main drive shaft turns the idler roller, and this idler roller in turn, turns the roller on the pitch control drive shaft in a direction which tends to stop the rotation of the impeller. This result may be accomplished with or without a load on the impeller main drive shaft. If there is no load on the drive shaft then the impeller completely feathers itself and stops. If there is a load on the main drive shaft then the pitch setting of the blades will be one that balances, without causing rotation. When the rollers are disengaged, the roller l6, its shaft 14 and the flexible shaft l9 may be readily rotated by hand to actuate the traversing guides and their associated elements.

While I have shown but one embodiment of my invention, it is susceptible to modification without I do not wish, therefore, to be limited by the disclosures set forth, but only by the scope of the appended claims.

-The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

I claim:

1. A variable pitch impeller for driving the reel of a tow target including, a rotatable shaft, a hub mounted on the shaft and having a plurality of radial sockets, a blade having its root rotatably.

mounted in each socket, a spur gear carried by the root of each blade, gear racks reciprocably mounted in the hub in meshing engagement with the spur gear for adjusting the pitch of the blades, a member slidably mounted on said shaft and fixed against rotation relative thereto, the member having connection with the gear racks for reciprocating the same, a worm gear rotatably mounted on said shaft and having screw-threaded connection with said member, a worm drive for imparting rotation to the worm gear so as to slide said member and actuate said gear racks, a control mechanism having a pair of spaced rotatable rollers, a flexible shaft operatively connecting one of the rollers to said impeller shaft, the other roller being operatively connected to the worm drive, means connected to said latter roller permitting manual rotation of the same so as to eifect adjustment of the blade pitch, an idler roller adapted to be moved into engagement with said rollers whereby the rotation of said impeller shaft is transmitted to said Worm drive, springpressed means supporting the idler roller out of engagement with said rollers, and cam means engageable with the spring-pressed means for moving said idler roller into engagement with said rollers.

2. A variable pitch impeller including, a rotatable shaft, a hub mounted on the shaft and having a plurality of radial sockets, a blade having its root rotatably mounted in each socket, gear teeth carried by the root of each blade, gear racks reciprocably mounted in the hub in meshing engagement with the gear teeth for adjusting the pitch of the blades, a member slidably mounted on said shaft and fixed against rotation, the mem- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,670,099 DAsseler May 15, 1928 2,144,007 Austin Jan. 17, 1939 2,164,489 Berliner July 4, 1939 25 2,206,874 Briner July 9, 1940 2,316,538 Lea Apr. 13, 1943 2,368,761 Hogan Feb. 6, 1945 FOREIGN PATENTS 39 Number Country Date 547,127 France Sept. 13, 1922