US1901953A - Propeller with automatic regulation - Google Patents

Description

March 21, A, E A 1,901,953

PROPELLER WITH' AUTOMATIC REGULATION Fig; July 8, 1951 2 SheetsSheet 1 ACHILLE FERRARIO INVENTOR ATTORNEYS March 21, 1933- A. FERRARIO PROPELLER WITH AUTOMATIC REGULATION ACHILLE FERRARIO Z mw m. m M ,m

Patented Mar. 21, 1933 UNITED STATES PATENT OFFICE AGHILLE raammo, or MILAN, ITALY r aornmaa wrrri auromarrc REGULATION Application filed July 8, 1931, Serial No. 549,421, and in Italy New 27, 1931.

The invention has for its object improve-' ments in motive, propulsive and tractive propellers, with variable pitch. These improvements render the propeller itself autoregulatable, in such a manner that thevariation of the pitch may be produced automatically in action by the speed of rotation of the said propeller.

With this object, the two opposed blades of the propeller are arranged, according to the present invention, in such a manner as to pivot around a common axis of rotation situated in'the plane-of the generator or motor or according to-the per endicular to this plane, the position taken 8 being determined by a device acting under theinfluence' of centrifugal force and which, consequently, is dependent upon the speed of revolution of the propeller. r The invention concerns, a;l so,m r pa ti larly the device rendering possibLe the automatic rotation and control ofthe blades around their common axis mentioned above, as also the method of constructing the centrifugal force regulator intended to con trol this rotation and to maintain, consequently, the blades inithe desired setting.

Finally, the invention comprises the devices constituted by a compensator applicable to the aforesaid centrifugal force regulator and having as its object to kee the variation of the speed of rotation of t' e propellgr due to the variation of the speed of the vehicle, ship, dirigible, airplane or the like on which it is mounted within limits as restricted as possible.

In the accompanying drawings, these various devices have been represented dia- {m grammatically by way of example.

lln these drawings: I Figure 1 is a front view of the propeller in line with the axis of revolution- Figures 1a and 1?) illustrate opposite discs 5 forming parts of the propeller.

Figure 2 is a plan view of the same propeller.

Figure 2a illustrates a support block of the device.

Figure 3 is a vertical transverse section y the blades through the axis of revolution .e-z of Fig ure 2.

Figure 4 is a'vertical section through line yy of Fig. 1. r

- Figure 4a is an enlarged section of a sleeve to disclose its details.

Figures 5 and 5a are a pair of opposlte plates of the propeller.

Figure 6 is one of the assembly plates for the spring of the same. 6

Figures 7 and 8 show respectively a view of the whole of the double system of the pro peller, and a disc of the same provided with two suitably balanced sectors.

At l1'- (Figure 1) are the two blades of the propeller which, in view of their diametrically opposed position, must pivot or rotate in a contrary direction. These blades form one body withthe hubs 2-2. The said hubs turn, through the medium of ball bearings intended to reduce the friction, on radial axes 3--3, which form a part of the support block 4 keyed upon the axis of the electric generator (assuming that the propeller is intended to drive a dynamo or a motor) in such a manner as to have the same axis. The support 4 thus turns with the axis of the dynamo or of the motor and the whole of the blades, but in relation to the mechanism which causes the variation of the pitch of the blades, however, it may be considered as. a fixed member. It is connected by a flange 4' with a corresponding flange arranged at the extremity of the shaft of the generator. llhe support 4. which supports the axes 3--3" on which the hubs of the lades turn is rovided, in addition, in its central part wit apertures and flutings intended to diminish the weight. Inside the support 4 a helical spring 5 is mounted coaxially with the axis of rotation of the propeller.

The method of organizing the automatic regulating mechanism serving for balancing the contrary rotation oi? the two blades 1-1 and the deflection of the spring 5, is as 95 follows:

The hub 2 of the blade 1 is connected (by means of. a flange and screws) with a disc 6, suitablybala-nced, and which is connected, in its turn, to the plate 6' by means of the two stays 7-7 The two discs 6--6' form one solid whole, with the difference, however, that while the disc 6 is fixed to the axis 3, the disc 6' is loosely mounted on the corresponding axis 3 (with interposition of a ball bearing). The result of this is that the rotation of the system formed by the blade 1, the hub 2, the disc 6, the stays (or tierods) 7-7 and the disc 6' is absolutely independent ofthe rotation which is impressed on the opposite blade l vunder the regulating influence of the system.

In its turn, the blade 1', with its hub 2', is rigidly connected with the disc 8 by means of stays 99. The disc 8, in its turn, is connected to a similar disc 8 which is situated in the opposite position with relation to the axis of revolution .a2. This system is similar to the preceding one; it participates in the rotation of the blade 1, but it is independent of the rotation of the blade 1.

By suitably arranging the stays 77' and 9-9, the two systems may receive oscillations of the same amplitude but in a contrary direction without mutually impeding each other.

The manner in which the device in question may be utilized with the View desired for automatically regulating the pitch of the propeller will now be explained.

With this object, the two stays 7 and 9, which shall be assumed to be arranged outside a plane coinciding with the blade axis y-y but symmetrically with relation to the axis of revolution z-2, are provided, in a plane along line m-m, with two dead heads 1010' which constitute the regulating masses which cause the usual balls of the centrifugal regulator to function.

Due to the action of centrifugal force, which originates during the revolution of the propeller, the dead heads 1010 tend to become removed from the axis of revolution, thus making the blades turn upon axis gay in such a manner as to modify their pitch precisely in such a dfi' ection that when the translation speed increases the pitch diminishes, thus creating a greater resistance which tends to return the propeller to its normal speed of rotation. If on the contrary, the speed of translation diminishes, the pitch also diminishes, from which there results a decrease in the resistance of the propeller which tends to return to its normal speed.

The turning of the blades is obtained by the displacement of the dead-heads which must at the same time act on the helical spring 5, determining, according to the case, an increase or decrease in the compression of this spring. In this manner, the system is put into a state of equilibrium when the moment of the centrifugal force of the dead-heads is equal to the moment of the compression of the spring. Therefore, it is thus possible to keep the revolution uniform of the propeller and,

consequently, of the dynamo or of the motor between limits determined by the construction of the system, but which, in any case, will be sufiicient in practice.

This result is obtained in the following manner: the two dead-heads 10-10, during the revolution of the system, become displaced by the eifect of centrifugal force on an arc (Figure 3) having its centre at 0 on the axis yy (Figure 3). These dead-heads are removed from the axis of revolution 22 when the speed increases and return to it when the speed diminishes, The regulation of the whole of the mechanism is effected in such a manner that the displacements of the two (lead-heads are equal. In their trajectory, the dead-heads slide upon a' rectangular plate 11, influenced'by the tension of the spring 5 which acts on this rectangular plate in such a manner as to push it toward the exterior.

The plate is therefore submittedto two contrarily directed forces, namely: theexpansive force of the spring '5 and the. centrifugal force tending to resist the spring. In

. other words, centrifugal force acts at right angles to the axis y-y of rotation of the blades, while the compression-spring 5 tends to push the dead heads 10 -10 out of their right angle position so as to produce-a balance of forces. When these two forces are in equi librium, the plate 11 has taken a determined position and, consequently, the opposed blades have assumed a given inclination, equal for the two blades but in a contrary direction, which determines the degree of their pitch.

The action of the system results from the simultaneous action of two independent regulators acting simultaneously on the spring 5 which determines, for any. degree of compression of the spring, a given inclination of the blade, the result of which is that the speed of revolution of the propeller is maintained substantially constant. The rectangular plate 11 is ordinarily level; but it is possible, if desired, to improve the isochronism of the system by giving this plate a slight curvature, the profile of which may be planned by points (Figure 6).

its movement, the plate is guided in two opposed slots 12 (inwhich catches 13 slide), as may be seen in Figure 3. These slots are formed upon a sleeve 14 rigidly connected to the support H. Thespring 5 is placed in the space between this sleeve and the internal cylindrical wall of the support.

In order that the system may function regularly, it is necessary to regulate in the first place the relation between the compression of the spring and the weights of the regulating masses. This is obtained by calculation; however; the spring 5 comprises a device intended to regulate its initial tension.

Thus, the plate 11 which presents at its centre a circular hole, slides upon the sleeve In Figure 4:, the sleeve is represented in greater detail, wherein it may also be seen how the mounting and the blocking of the propeller at the.end of the shaft 20 of the generator is effected. This shaft ends conically and has a threaded cylindrical extremity 21 upon which the plug 22 is screwed. The blocking is efl'ected by means of the screw-threaded ring 23 and the extremity of the plug 22 is recessed on its circumference in such a manner as to] be able to stop it by means of a key for blocking or releasing the plug. It will be understood that after having removed the ring 23 and released the plug 22 by means of the key it will be p0ssi ole to easily screw the propeller on to the shaft.

With the obj ect in view of maintaining the have an angle which may be equal to the maximum angle of rotation which must be carried out by the system to pass from the position corresponding to the minimum position of the vehicle, ship, dirigible, airplane or the like to which the propeller is fitted to the position corresponding to the maximum speed or even to the double of this angle. All these sectors give rise to a centrifugal force applied to their centre of gravity and directed in such a manner that the moment of rotation is opposed to that of the principal regulating dead-heads, from whence results a correcting action on these deadheads. Owing to these sectors and by suitably regulating the additional masses, is possible to keep the deviations of speed within restricted limits. practically realizing the isochronism. The best arrangement consists in rendering the angle of the sector equal to the maximum angle of rotation, as stated above. The correcting masses in the-form of plates indicated in Figures 5 and 5a, are applied to the disc of one system (66') in an opposite direction to the discs of the other system (8-8) in the respective positions 19 and 19'. The sectors represented in these figures have a circular form, but could also be made differently.

Whatever the general arrangement of the system may be, it is easy to understand that it is possible to double it (Figure 7) by then utilizing four regulating masses and two rectangular plates by which the compression of the spring is acted upon. There results from this the possibility of applying the mechanism better, and the elimination of shocks on the axis of the spring which are thus balance The central part of the propeller which contains the device for varying the pitch mentioned above is preferably protected by means of a cap presenting. externally a stream-line form.

What I claim and desire to secure by Letters Patent of the United States is 1. A motive, propulsive or tractive propeller, including the combination with means for mounting the same, of a pair of ppposite rotatable blades having a common axis of rotation, and means for determining the amount of such rotation and thus the pitch of said blades by the effect of centrifugal force during revolution of said propeller, including a compression spring coaxially mounted with the axis of revolution of the propeller, a dead head associated with each blade and swingable outward about the longitudinal axis thereof thereby tending to directly rotate the blade, and'a plate upon said I fect of said dead heads.

2. A motive, propulsive or tractive propeller, including the combination with means for mounting the same, of a pair of opposite rotatable blades having a common axis of rotation, and means for determining the amount of such rotation and thus the pitch of said blades by the eifect of centrifugal force during revolution of said propeller, including a pair of dead heads individually associated with said blades and swingable outward about the common longitudinal axis thereof, thereby tending to directly rotate said blades in opposite directions about said axis, and means governing the extent of centrifug'al swing of said dead heads in opposition to the eifect of centrifugal force thereon, comprising a plate disposed in contact with said dead heads and movable thereby to a limited extent in line with the axis of revolution of the propeller.

' trifugal swing of'said dead heads in opposition to theeffect of centrifugal force thereon, comprising a plate disposed in contact with said dead heads and resiliently movable thereby to a limited extent in line with the axis of revolution of the propeller as a whole.

4:. A motive, propulsive or tractive propel ler, including the combination with means for mounting the same, of a pair of opposite rotatable blades having a common axis of rotation, and means for determining the amount of such rotation and thus the pitch of said blades by the effect of centrifugal force during revolution of said propeller, including a pair of dead heads individually associated with said blades and swingable outward about the common longitudinall xis thereof, thereby tending to directly rotate said blades in opposite directions about said axis, and means governing the extent of centrifugal swing of said dead heads in opposition to the efiect of centrifugal force thereon, comprising a plate in'contact'with said dead heads and movable thereby in line with the axis of revolution of the propeller as a whole, and a spring mounted coaxially with said axis of revolution supporting said plate and resiliently resisting motement of the plate by said dead heads.

5. A propeller according to claim 1 in which the plate in contact with the dead heads is curved in form.

6. A propeller according to claim 4 wherein the plate in contact with the dead heads is arcuate in form upon the contact portion thereof for said dead heads.

7. A motive, propulsive or tractive propeller, including the combination with means for mounting the same, of a pair of opposite rotatable blades having a common axis of rotation, and means for determining the amount of such rotation and thus the pitch of said blades by the effect of centrifugal force during revolution of said propeller, includin a plurality of dead heads associated witeach of said blades and swingable outward about the common longitudinal axis thereof, thereby tending to directly rotate said blades in opposite directions about said axis, and means governing the extent of centrifugal swing of said dead heads in opposition to the efiect of centrifugal force thereon, comprising a compression spring mounted coaxially with the axis of revolutionof the propeller and a pair of plates individually disposed upon the ends of said spring in contact with said dead heads and movable thereby against the action of said spring .along said propeller axis.

8. A propeller according to claim 4 wherein the plate in contact with the dead heads is slidably mounted on a sleeve coaxial with the main propeller axis, and a second outer sleeve enveloping at least a portion of said first sleeve, the compression spring being mounted upon said first sleeve within said second sleeve.

9. A propeller according to claim 2 wherein a disc is rigidly associated with each propeller blade and provided with a rod carrying the dead head referring to said blade.

10. A propeller according to claim 7 wherein a disc is rigidly associated with each propeller blade and provided with a rod carrying the dead heads referring to said blade.

11. A motive, propulsive or tractive propeller, including the combination with means for mounting the same, of a pair of opposite rotatable blades having a common axis of rotation, and means for determining the amount of such rotation and thus the pitch of said blades by the effect of centrifugal force during revolution of said propeller, including a Pair of dead heads individually associated with said blades and swingable outward about the common longitudinal axis thereof, thereby tending to directly rotate said blades in opposite directions about said axis, and means comprising comnsating members associated with the dead eads governing the extent of centrifugal swing of said dead heads in opposition to the efiect of centrifugal force thereon, whereby to correct the effect of the centrifugal force on said dead heads.

ACHILLE FERRARIO.

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