Abstract: A centrifugal fan includes a fan wheel having airfoil blades mounted for pivotal movement about their center of gravity. A yoke mechanism exterior of the fan wheel, when moved axially of the fan wheel drive shaft axis, causes actuator rods to move through the sidewall of the fan wheel. The axial movement of the actuator rods is translated first into rotary movement of a quill hub relative to the fan wheel and finally to radial movement of blade pivoting levers interior of the fan wheel. The movement of the blade pivoting levers causes the pitch of the individual fan blades to be changed in accordance with the degree of movement of the yoke mechanism. The yoke mechanism, actuator rods, quill hub and blade pivoting levers operate independently of the fan wheel so that blade pitch can be varied over an operating range irrespective of whether the fan wheel is stopped or is rotating.

Abstract: An axial flow fan with adjustable blades 18 has a spindle 16 for each blade mounted in a hub rim 12. Each spindle has associated therewith a replaceable cartridge 58 having a thrust bearing 70 therein and spaced radial bearings 64, 70. In order to service the bearing, the cartridge can simply be disconnected, e.g. by unscrewing from the rim having removed the blade 18.

Abstract: A low profile, externally controlled, variable pitch fan blade hub assembly is disclosed which is especially useful in high humidity environments such as are encountered in the fan induced, hot air discharge section of an industrial water cooling tower. The hub housing has central hub means including a member which is telescoped over the drive shaft therefor to limit the overall height of the assembly. The hub member is biased axially of the hub by a series of peripherally located springs contained within the housing. A fluid such as air may be introduced into the housing under pressure to shift the hub unit in a direction against the spring bias thereon. The housing has a plurality of radially extending bores each of which rotatably receives a respective fan blade axle provided with an elongated arm on the innermost end thereof within the housing positioned such that a cam follower on each arm is received in a cam track forming a part of the hub unit.

Abstract: A controllable pitch propeller assembly has an inner housing attached to a main drive shaft, the housing having rails on the outer surface thereof. Modules carrying the propeller blades are positively mounted on the rails, each module having a housing receiving a hub cylinder and bushings axially aligned at opposite sides thereof. Each pair of bushings receives an adjusting piston having an adjusting pin which engages a groove forming a control path in a propeller hub. Each blade is adjusted by a control lever which adjusts each adjusting piston through a mechanical linkage including an adjusting sleeve and a thurst bearing and flange.

Abstract: Axial flow fan blade roots (1) are rotatably journalled to blade shafts (4) by bayonet plug and socket couplings. The socket recesses (30, 31) provide an axial play for the plug cam portions (28, 29). Screws (34, 35) extending through the blade root (1) have shoulders (43) abutting spring members arranged between the root and the shaft to thus bias the blade outwardly and establish frictional engagement between the bayonet coupling cam portions and recesses.

Abstract: An axial flow machine particularly a blower, has rotor blades external to a housing and each blade is supported by a respective strut which is rotatable about its respective strut axis to adjust the orientation of the blades. A respective crank-like swing lever attached to each strut is movable to rotate the strut. Each swing lever has a slide block at the end thereof which is carried in the annular peripheral groove of an axially movable adjustment part. As the adjustment part is displaced axially, the swing levers rotate in their slide blocks. The invention is concerned with lubricating the rotation of the swing levers in the slide blocks. The adjustment part is at least partly inundated by an oil supply held in the housing. The adjustment part is scoop shaped. The rim of the adjustment part includes an annular peripheral wall on the exterior of which the peripheral groove is defined.

Abstract: The assembly includes a propeller shaft, a hollow hub closed at one end and secured at its other end to said shaft, a space being formed within said hub, said hub carrying blades which are rotatably driven by said shaft and hub and are changeable in pitch, a crosshead supported within said space for axially reciprocatable movement and coupled to said blades so as to change the pitch of said blades as said crosshead reciprocates, said crosshead having an end part adjacent said shaft and said end part forming a piston that is slidable on the inner surface of said hub, said piston defining on one side thereof a first chamber formed by said piston, said hub and said output end of said shaft, and defining a second chamber on its opposite side, formed by said piston and said hub, each of said chambers being adapted to be supplied individually with hydraulic fluid. The blades are rotatably connected to the hub, and the connection includes two spaced seals.

Abstract: A windmill having blades with both variable pitch and variable spanwise twist. The windmill includes a hub which may be supported on top of a tower for rotation about a substantially horizontal axis. A plurality of blades are provided, each having a root, a tip and a spanwise twistable intermediate section. Linkage mechanisms connect the roots of the blades to the hub to permit selective independent rotation of the roots and the tips of the blades for varying the pitch and the spanwise twist of the blades. An electric power generator is drivingly connected to the hub. A control mechanism is connected to the linkage mechanisms for varying the pitch and spanwise twist of the blades in accordance with a predetermined desired relationship.

Abstract: A variable pitch propeller is disclosed having a crank arm attached to the shaft of each propeller blade and a telescoping drive arm having one end pivotally attached to the propeller hub and the other end pivotally attached to a control rod. The telescoping arm rotates the crank arm to adjust the pitch of the propeller blades through an angle substantially greater than 90.degree. as the control rod is moved longitudinally along the longitudinal axis of the hub of the propeller.

Abstract: A controllable pitch propeller has a plurality of connecting rods running from a piston, through the end wall of a cylinder. The cylinder is affixed to a first set of blade turning crankpins forming part of a blade turning assembly. A piston, mounted for axial movement in the cylinder, is coupled to the connecting rods that in turn are connected to a second set of blade turning crankpins in the blade turning assembly. The piston and cylinder are relatively movable to rotate the blades through the crank pins. Due to normal tolerance variations during manufacture, the lengths of the total train of connections between the piston and the cylinder through the blade turning assembly are not identical, causing the length of the portion of the connecting rods protruding into the cylinder through the cylinder end wall to vary relative to the cylinder end wall.

Abstract: A variable-pitch propeller has a hollow hub rotatable about a hub axis and carrying a plurality of angularly equispaced vanes each rotatable on the hub about a respective vane axis extending radially of the hub axis. Each of the vanes has an eccentric pivot pin parallel to its respective vane axis and connected via a bearing to one end of an arm formed on an adjustment member displaceable in the hub along the hub axis and rotatable in the hub about the hub axis. The bearing allows for rotation of the pivot pin relative to the arm in which it is received and for displacement of the pivot pin along the pivot axis relative to the arm receiving it. Thus axial displacement of the adjustment member will force the pivot pins to orbit limitedly about the respective vane axes with concomitant sliding of the bearing along the pin and simultaneous rotation of the adjustment member in the hub.

Abstract: A pitch-change apparatus for a ducted thrust fan having a plurality of variable pitch blades employs a camming ring mounted coaxially of the hub at an axially fixed station along the hub axis for rotation about the hub axis both with the blades and relative to the blades. The ring has a generally spherical outer periphery and a plurality of helical camming grooves extend in a generally spherical plane on the periphery. Each of the variable pitch blades is connected to a pitch-change horn having a cam follower mounted on its outer end, and the camming ring and the horns are so arranged about the hub axis that the plurality of followers on the horns engage respectively the plurality of helical camming grooves. Rotary drive means receives pitch-change commands from an appropriate controller and rotates the camming ring relative to the blades to cause blade pitch to be changed through the cooperative operation of the camming grooves on the ring and the cam followers on the pitch-change horns.

Abstract: A sail-type wind-driven prime mover is provided in which the area of the sails facing into the wind is adjustable. The prime mover comprises a drive shaft from which depend radially extending front and rear masts which support flexible sails. The area of the sails facing into the wind can be varied by moving the rear masts along and about the drive shaft while keeping the front masts fixed relative to the drive shaft. In a preferred embodiment in which the prime mover drives an electric generator, means are provided to automatically adjust the sails as a function of the output voltage of the generator.

Abstract: Each fan-blade carries a bevel-pinion in mesh with two bevel ring-gears which are driven in rotation in opposite directions by means of two coaxial cylindrical tubular members. Carriages are mounted for axial motion within the space formed between the two tubular members; balls are fitted in helical grooves formed at opposite angles of slope in the internal and external cylindrical faces of the carriages and in corresponding helical grooves formed in the adjacent faces of the tubular members so as to form a ball-race. The moving member of at least one axial hydraulic jack constituting a motor is coupled to the carriages and the stationary member is coupled to the fan-shaft.

Abstract: A pitch-change apparatus for a ducted thrust fan having a plurality of variable pitch blades employs a rotatable ring bearing a plurality of camming members, and each of the plurality of blades is connected with a pitch-change horn engaged by one of the camming members. The ring and camming members rotate coaxially about a hub axis with the blades and rotate about the hub axis relative to the blades to collectively change blade pitch. The rotatable ring, the camming members and the pitch-change horns develop a variable mechanical advantage, and the pitch horns are connected with their respective blades so that the minimum mechanical advantage corresponds with the low-load, feathered pitch position of the blades and greater mechanical advantages correspond with the higher load, forward and reverse pitch positions of the blades.

Abstract: An improved actuating mechanism is provided for a gas turbine engine incorporating fan blades of the variable pitch variety, the actuator adapted to rotate the individual fan blades within apertures in an associated fan disc. The actuator includes means such as a pair of synchronizing ring gears, one on each side of the blade shanks, and adapted to engage pinions disposed thereon. Means are provided to impart rotation to the ring gears in opposite directions to effect rotation of the blade shanks in response to a predetermined input signal. In the event of system failure, a run-away actuator is prevented by an improved braking device which arrests the mechanism.

Abstract: In an axial flow fan impeller, the natural frequency of vibration of the individual blades is increased by mounting each blade to the annular support rim or hub for swinging movement relative to the ring about an axis, which lies generally perpendicular to a radius passing through the mounting. For a given blade, the mounting enables the fan to be rotated at higher speeds with a corresponding increase in performance. The mounting also permits the use of thinner, lighter-weight blades for a given operating speed and this permits a reduction in the cross sectional area of the rim. If the impeller includes a mechanism for controlling the pitch of all the blades during operation, the use of lighter-weight blades reduces the stresses on the mechanism so that the design and strength of the latter does not tend to be a limiting factor on the maximum permissible speed for the impeller.

Abstract: A fan assembly particularly adaptable for use with an induced draft heat exchanger having a fan with a plurality of variable pitch blades, a drive mechanism and a pitch control mechanism, wherein the drive mechanism and the pitch control mechanism are designed to be located upstream of the heating element on the cool-air side of the heat exchanger. The pitch control mechanism is coupled directly to the rotating fan shaft, separate from the frame member for the heat exchanger to prevent problems in the alignment of the bearings for supporting the fan assembly. A fail safe mechanism is also provided in the rotating assembly of the fan to insure maximum pitch of the fan blades if the pitch control mechanism fails.

Abstract: A variable pitch propeller assembly having a shaft mounted in a housing and operably connectable to a rotary power source. A means mounted on the shaft has a propeller blade pivotally mounted therewith. The blade has a stem portion pivotally mounted in the means. A cam is rotatably mounted in the housing and has an inclined portion angularly disposed relative to the shaft. Another means is slidably mounted in the housing and positioned between the cam and the first-named means and having a cam follower engaged with the inclined portion of the cam and having a guide means oppositely disposed to the cam follower. A rotatable member is positioned between the means slidably mounted and the first-named means and it has guide means follower engaged with the guide means and members connected with the stem portion of the propeller blade.

Abstract: A rotor pitch control mechanism for use with bearingless helicopter rotors is disclosed. The disclosed mechanism eliminates the requirement for vertical motion of the pitch link, thus alleviates the bearingless rotor problem of flapwise motion of the rotor blade in response to pitch control actuator forces. Stabilizing pitch-flap coupling and blade flap restraint is provided.