DE29511046U1 - Pressure cone for folding propellers - Google Patents

Description

Description:

In the folding propeller described, the central piece is the replaceable component. It determines the number of propeller blades. The hub and pressure cone are identical in all variants.

The pressure cone is new . This element uses a compression spring to push the propellers into the folded resting position and holds the propellers in this position.

At the same time, the pressure cone with its largest diameter serves as a defined stop for the blades. This allows a definable and repeatable size of the folded propeller to be achieved.

In this final position, the propellers are also secured against snagging among each other.

A further advantage of the described design is that commercially available propellers can be used without any modifications or adjustments.

The dimensioning of the compression spring or its spring constant can be determined by determining the forces using a force triangle.

The pressure cone applies the components required for folding to the elements

-Spring, as an energy source and

-Cone as a force transmission element reduced.

As a rotationally symmetrical component, the pressure cone does not need to be secured against twisting.

Problem:

Folding propellers are designed to be folded in when not in use to save space, so that the drive unit can be easily accommodated in the hull of the sailboat.

The folding process requires a force that counteracts the gravity of the propellers and holds the propellers in a defined position.

State of the art:

Folding propellers are folded in different ways;

With torsion spring at the pivot point

With tension or compression spring via leverage

With forced control via lever action on the propeller blade With elastomer rings via lever action on the propeller blade

Solution:

The PAK system works with a pressure cone, which serves as a force transmission element, e.g. via spring action, and transmits the force to the propeller via its outer surface.

An axial displacement of the thrust cone in the direction of flight causes the propellers to move into the rest position.

The centrifugal force that occurs when the propeller rotates, in conjunction with the mass of the propeller blades, causes the propeller blades to unfold (operating position).

Further design:

The folding propeller, which consists of 3 main components (hub, central piece, pressure cone), can be operated as a 2-, 3-, 4- or 5-blade propeller. Systems with more than 5 propellers are conceivable, but are less efficient.

Folding propeller PAK

Possible uses:

Use of the folding propeller in aircraft propulsion, especially in electric motor-driven model gliders.

For example, a folding engine is provided for the use of the folding propeller. Folding engines of gliders are drive units that are completely housed in the glider's fuselage.

They are mechanically extended, unfold their propeller and take the aircraft to a freely selectable altitude. This altitude is limited by the energy on board, depending on the efficiency of the drive unit and the aircraft.

For the example chosen, a folding engine is used that works as a parallelogram construction. When folding into the fuselage, no relative rotation of the drive unit to the fuselage axis takes place; the folded propeller is retracted parallel to the fuselage axis over its greatest length.

Construction:

* Hub is mounted on the output shaft of the motor

* Central piece is screwed to the hub and secured with a positive fit

* Propeller blades are rotatably mounted on the central piece

How it works:

* Pressure cone pushes propeller blades from operating position to folded rest position

* Pressure cone serves as a defined stop in the rest position

* Propeller unfolding via centrifugal force

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Key to symbols

1 - Folding propeller in operating position

2 - Electric motor

3 - Folding propeller in rest position

4 - 2-blade center piece

5 - Hub

6 - Pressure cone

7 - Stop for propeller blades

8 - 3-blade center piece

9 - 4-blade centerpiece

10 - Propeller

11 - Unfolding rotation of the propellers

Claims (1)

WW www www Claim for protection: The component of the folding propeller that needs to be protected is the pressure cone, which can be used variably for 2-, 3-, 4-, 5-blade propellers. The pressure cone is movably mounted on the hub. It is not secured against twisting. As a force transmission element, the pressure cone is actuated by a spring. The surface of the cone acts like a wedge on the propeller blades and moves the propeller blades into the rest position when they are at a standstill. The maximum diameter of the thrust cone defines the rest position of the propeller.