US2495433A

US2495433A - Pitch adjusting mechanism

Info

Publication number: US2495433A
Application number: US537567A
Authority: US
Inventors: Theodor H Troller
Original assignee: Joy Manufacturing Co
Current assignee: Joy Manufacturing Co
Priority date: 1944-05-27
Filing date: 1944-05-27
Publication date: 1950-01-24
Anticipated expiration: 1967-01-24

Description

Jan. 24, 1950 T. H. TROLLER FITCH ADJUSTING MECHANISM 2 Sheets-Sheet l Filed May 27, 1944 HVVENIUR.

www ccd2 Jan 24, 1950 l T. H. TROLLER 2,495,433

FITCH ADJUSTING MECHANISM Filed May 27, 1944 2 Sheets-Sheet 2 //kU//A D/efcnon/ of (brano/V Y MMM Patented Jan. 24,1950

UNITED STATES PATENT l OFFICE FITCH ADJUS'HNG a eorporatlon of Pennsylvania my 27, 1944. Schl No. 537,567

2 Claima- (CL 17o-160.16)

l The invention relates -in general to variab pitch propellers and more particularly to a mechanism for adiusting the pitch of the propeller blades of fans.

An object of the invention is the provision of an improved pitch adjusting mechanism which is simple in construction, easy to and operable to vary the pitch of the blades while the fan is operating.

Another object of the invention is the provision of an improved pitch adjusting mechanism including a rotatably mounted disc member having an annular face adapted to press against arms which are connected to the blades and'which when the arms are moved provide for rotating the blades.

Another object of the invention is the provision of an improved variable pitch propeller lmounted upon a drive shaft with the blades actuated to various pitch angles by an axially movable disc member which is carried by the shaft and which presses against arms connected to the blades for rotating the blades to vary their pitch angle.

Another object of the invention is the provision of improved pitch adjusting mechanism including means for individually adjusting the pitch angle of the blades for a fixed axial position of .the actuating disc member which controls the joint operation of all the blades.

Another object of the invention is the provision of an improved pitch adjusting including anaxially movable disc member which controls the pitch of the blades and which does not interfere with the assembling or dismantling of the blades or associated parts.

Another object of the invention is the provision of an improved pitch adjusting mechanism including spring means connected to each of the arms of the blades for exerting a force to oppose the movement of the arms by the actuating disc member.

Other objects and a fuller understanding of `the invention may be had by referring to the following description and claims, taken in conjunction wi-th the accompanying drawings. in which:

Figure 1 is a longitudinal sectional view of an embodiment of the invention taken along the line I-I of Figure 3 and with parts shown in elevation and portions of some parts broken away;

2 the line 3 3 of Figure 1, with the noselike cover removed to show the actuating disc member which presses against and operates the arms connected to the shanks of the propeller blades for rotating the propeller blades for varying the pitch thereof; and

Fgureiisaviewtakenalongthelinel-Iof Figure 2.

My invention is being illustrated and described in connection with a variable pitch fan but -it is to be understood that it applies to variable pitch blades of all kinds.

As illustrated in the drawing, the variable pitch fan is designated generally by the reference character I I and is arranged to be rotatably mounted within an outer annular duct I0 which may be connected in any suitable duct system for distributing the fan driven air. The variable pitch fan II may be driven by any suitable means and as shown in the drawings, the fan is driven by an electric motor Il which may be mounted within an inner annular housing I5 which is supported substantially concentric within the outer annular duct I0 by means of stationary guide vanes I6.

The variable pitch fan II comprises, generally,-

a rim I2 and a plurality of blades I3 having shank portions 24 rotatably mounted within the rim I2 by means of ball bearing units 25 whereby the blades may be easily turned by the pitch adjusting mechanism. The rim I2 is provided with a web I8 which is arranged to be mounted upon the motor shaft I1 by means of a nut I9. As is manifest, the motor shaft I1 supports and drives the complete fan assembly which greatly facilitates the mounting of the variable pitch fan within the `outer annual duct I0.

Adjustably mounted upon the inner end of each of the shank portions 2l of the fan blades is an actuating arm 21. As shown best in Figure 4, the actuating arms 21 extend outwardly from the shank portions 24 and are arranged to be actuated by an actuating disc member 2B which is rotatably mounted upon a shaft extension 3l of the motor shaft I1. As shown in Figure 1, the lefthand side of` the actuating disc member 29 may be provided with a wear face plate 3B which presses against the ends of the actuating arms 21 for varying the pitch of the fan blades I3. The actuating arms 21 are adjustably mounted upon the shank portions by means of nuts 26. The propeller blades I3 may be each individually adjusted with respect to a xed axial position of the actuating disc member 29 by loosening the nuts 2i and turning the blades to their correct position, after which the nuts 26 may again be the actuating disc member 29.

3 tightened. Consequently, as the actuating disc member 29 is axially moved upon the shaft extension 3|, the blades turn simultaneously to vary their pitch angles. A spring 28 is associated with each of the actutaing arms 21 to exert a force in opposition to the movement of the arms by the actuating disc member 29. As shown best in Figures 2 and 4, one end of the spring 28 is connected to the actuating arm 21 and the other end of the spring is arranged to fit against the web I8 which supports the rim of the variable pitch fan. Accordingly, the springs 28 hold the actuating arm against the wear face plate 30 of Under running conditions, the action of the centrifugal forces and/or the air forces upon the blades is such as to constrain the ends of the actuating arm 21 against the wear face plate 30, in addition to the spring pressure.

The axially reciprocal movements of the actuating disc member 29 is governed by a control rod 35 which is actuated by a control lever 36 having one end 39 pivotally connected to one side of the outer annular duct IU and having its other end 48 extending externally of the outer annular duct I for external actuation. The control rod 35 extends through an opening 38 in a nose-like cover 31 which may be suitably connected to the forward edge of the rim I2, such for example, as by a crimped edge 4I which resiliently engages a bead 42 provided on the internal surface of the rim of the fan. As illustrated, the control rod 35 is connected to the hollow hub 32 of the actuating disc member 29 by means of a ball bearing unit 34, whereby the actuating disc member 29 may rotate upon the shaft extension 3| as the variable pitch fan is operated. A bushing 33 is mounted inside of the hollow hub 32 and is arranged to provide a bearing surface with the extension shaft 3|.

In operation, the pitch of the fan blades is ad- It is noted thatthe actuating disc member 21 constitutes a very simple construction for varyinl the pitch of the fan blades and affords an eas: method of assembling the units inasmuch as therl is no necessity for the radial alignment of thu actuating arms 21 with respect to the wear fam plate 30.

Although I have described my invention wltt a certain degree of particularity, it is understoocl that the present disclosure has been made onli by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted tc without departing from the spirit and the scope of the invention as hereinafter claimed.

What I claim is:

1. A variable pitch propeller comprising a rotatably supported body having antifriction devices arranged thereon at points spaced circumferentially about the same and blades rotatably supported by said antifriction devices for turning on axes extending radially of said body but fixed against movement in either direction longitudinally of such axes, said blades so formed that the action of centrifugal force and of the air thereon as said body rotates produce a resultant torque sufficient to turn said blades on said axes,

arms fixed with respect to each of said blades and justably Varied by moving the control lever 36 f which in turn axially positions the actuating disc member 29 for holding the blades at a predetermined pitch angle as determined by the setting of the control lever 36.` The pitch of the blades may be varied While the fan is rotating and any suitable means may be employed to hold the outer end 40 of the control lever in a fixed position after the pitch of the blades has once been set or adjusted. During rotation of the fan, the centrifugal forces and/or the pressure of the air upon the blades I3 is such as to cause the actuating arms 21 to be pressed against the wear face plate 30 of the actuating disc member 29. When the fan is idle, the springs 28 continue to bias the ends of the actuating arms 21 against the Wear face plate 30 of the actuating disc member 29. The springs 28 may be dispensed With because just as soon as the fan has started to rotate the centrifugal forces, and/or the air forces, cause the blades to rotate in such direction as to cause the actuating arms 21 to press against the wear face plate 3B of the actuating disc member 29. In other words, should the actuating arms 21 be not contacting the wear face plate 30 when the fan is idle, they will beimmediately turned by the centrifugal forces and! or the pressure of the air acting against the fan blades I3 to immediately press them against the wear face plate 30. The ball bearing units 25 constitute antifriction bearings whereby the fan blades may be easily turned by the pitch adjusting mechanism when the fan blades are rotating.

projecting at least generally radially with respect to said axes, and arm angle controlling means including a member supported in coaxial relation with said body for rotation relative to the latter and for movement towards and from the latter along its axis of rotation, and having an annular surface on one face thereof with which said arms are frictionally engageable whereby changes in position of said member along a line including its axis of rotation, through the action of said surface on said arms, may change the angle of said blades to said body.

2. A variable pitch propeller comprising a rotatably supported body having antifriction devices arranged thereon at points spaced circumferentially about the same and with their axes in a common plane and blades held against radial movement by said antifriction devices but journaled by the latter for turning on axes extending radially of said body, said blades so formed that the action of centrifugal force and of the air thereon as said body rotates produce a resultant torque sufficient to turn said blades on said axes, arms adjustably secured in fixed relation to each of said blades and projecting at least generally radially with respect to said axes, and a member supported in coaxial relation with said body and turnable on its axis relative to said body and movable relative to the latter along the line of its axis of rotation, and having an annular surface on one face thereof with which said arms are frictionally engageable and which constitutes the sole contact with the latter of said member, and means for moving said member towards and from said plane whereby changes in position of said member along a line including its axis of rotation, through the action of said surface on said arms, may change the angle of said blades to said body.

THEODOR H. TROLLER.

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

(References on following page) Number :Mamas Number 0 Name Date Bellman Nov. 23, 1937 Williams Apr. 13, 1943 Dewey et al Apr. 20, 1943 Bebinger June 6, 1944 Stepanot! Sept. 12, 1944 Bebinger Sept. 19, 1944 Adams et al. Dec. 4, 1945