FR2714356A1 - Aircraft propeller hub mechanism for varying propeller pitch - Google Patents

Abstract

A sliding fork component acts against the root portions (6) of the propeller blades (8) via an intermediate roller bearing assembly. The fork may alternatively contact the blade roots via a rack and pinion mechanism, with a control pinion (14) driven manually, electrically, mechanically or hydraulically. The assembly is secured together by fastening screws in the interior of the mechanism, which may be reached by using a key to pass through holes in the hub casing (4). The connection between the fork and the propeller blades is such as to allow retro-fitting to existing propeller mechanisms of a range of designs.

Description

VARIABLE STEP PROPELLER HUB
The present invention relates to a mechanism for
replace a propeller & not fixed by a propeller & not varia
ble on any motor shaft or reduction output
of any aircraft or other system using a propeller - to generate relative movement of the environment by
relation to the system or vice versa.

Indeed, if we want to adapt a propeller & variable pitch,
it is almost always necessary to have a tree
hollow, either in the motor or in the reduction gear. However, the - present invention makes it possible to install very quickly a
system & not variable replacing a system & not
fixed without adding or transforming a mechanical element a
inside the motor or gearbox. Because of this, the demon
stage and reassembly of the new propeller, presenting - no difficulty, is protected by a simple mechanic
learning their material and does not necessarily require
specific skills for this kind of modification.

In addition, it must be admitted that the advantage of the propeller & not
variable no longer needed to be demonstrated: fuel economy at - cruising speed and adaptation of power to all
the phases of the flight (this is the "gearbox" of the aircraft),
or displacement.

The mechanism described below is fully integrated into the
hub, which has the advantage of being simple & easy to install.

 The invention is shown in cross section.

Fig.l. in the plane formed by the axes XX 'and AA'. The plate - (1) is the only part that is not part of the hub.
the propeller: it is the output of the engine or of the reduction gear which can
be of any shape and size. On this set
(1) is fixed. by bolts and nuts a suitable plate (2) on
which is welded a tree (3). I1 is & note that the plate - (2) and the shaft (3) can constitute only one piece.

At the end of the shaft (3), a part (4) transmits the rotation &
two symmetrical half-hubs (5), plating on each side
of plan XX ', and inside which are provided lodges
for receiving the bearings (17) and (18). The latter - provide rotation guidance along the axis XX 'of the axis of
blade root (6), as well as its stop in translation.

Around the shaft (3) two tapered bearings support a
fixed plate (9) fig. 1. coupled by welding & a screw (23).

 It should be noted that the plate (9) and the screw (23) can be made in one piece.

On this screw (23) comes to adjust a nut (24) over
which two bearings (19) and (22), locked by a SKF nut
(3), ensure the rotation and translation guidance of a
fork (11) which allows the movement of a roller (13) - fig.2. lodged in his throat. This roller (13) is fixed solidai
rement on a plate (12) fig.3. itself maintained soli
the axis (6).

OPERATION
The cynemaetic link is generalized fig.4.

In dark: the elements transmitting the engine torque and the
rotation around the axis AA '.

In clear hatching: the moving elements around the axis AA '- moving in slow rotation on the screw allow the dice
longitudinal placement of the fork and thus rotation
around the axis XX 'of the blade root. Clearly, without hatching:
the elements attached to the engine mount.

The rotation of the motor or the reducer materialized by its - output plate (1) drives the axis (3), integral with the
part (4), which is fixed on the two half-hubs (5), which
causes the blade roots (6), so the blades (8) in rota
tion around the axis AA '.

The operation of the pinion (14) meshing on the wheel (10) solid with the nut (24) causes the displacement of said nut
on the screw (23) fixed longitudinally with respect to the building
motor, and therefore involves moving the fork (11)
driving the roller (13) in a rotary movement around
the axis XX ′, hence a change in the orientation of the blade foot (6) integral with the blade (8) by means of the
assembly parts (7).

So we get the propeller pitch setting by simple
operation of the pinion (14), both when stopped and during
displacement in the ambient environment considered. The pinion (14) - can be controlled by any mechanical, manual, electric hub
that, hydraulic or other.

ASSEMBLY AND ADJUSTMENT
In fig. 1. and 2., note the presence of all designated
when passing an operating key for screws like IMBUS per
putting the fixing of the whole hub directly on the
output plate (1) of the motor or the gearbox, without dismantling the system. This allows interchangeability between the year
cienne propeller not fixed and the new propeller & not varia
ble, but also to guarantee the precision of the ef settings
carried out during manufacture and thus leaves the possibility
to make the mechanism untouchable for any unauthorized person, which is very useful on aircraft.

At the end of the axis (6) two half-hubs of the paddle-feet (7)
symmetrical allow the mechanical connection between the axis (6)
and the blade (8). These two half-hubs (7) are assembled between
them by 4 screws (26) and (27). The fact of having inserted
half-hubs allows to adapt several types of blades and
to have different final settings depending on the configuration
tion wanted.

Claims (1)

 I- Mechanism adaptable to any existing system without any  modification of the propeller shaft (gearbox output shaft  or motor).  II- Mechanism according to claim I characterized by the pitch  wise from the position "big-step, little-step, reverse" in con  continuous during operation or when stopped. III - Mechanism according to claims I and II characterized by  the axial displacement of a fork causing, by the in  intermediate of a roller, the blade root, thus controlling the  variation of the propeller pitch.  IV - Mechanism according to claims I A III characterized by  the fact that the pitch variation adjustment set is  killed by the fork and the pebble can be advantageously  replaced by a rack and pinion assembly which allows  fold the whole range of use from the "flag" position   & the "reverse" position. AT  V - Mechanism according to claims I & IV characterized by  the fact that the drive pinion (14) can be actuated by  any manual, electrical, mechanical or hydraulic means.  VI - Mechanism according to claims I & V characterized by  fact that the assembly is done without disassembly of the entire  hub, by fitting fixing screws inside  of the mechanism; these screws are locked by a key  passing through the practical holes through the assembly.  VII - Mechanism according to claims I & VI characterized by  the fact that the blade root adapters allow the uti  Lization of any type of blade, existing or fa  special connection without modification of the basic mechanism. VIII - Mechanism according to claims I to VII characterized by  the fact that it includes a system allowing to know the  value of the blade angle.