Locking device for cooling fan assembly

1. A cooling fan assembly comprising:

a central hub;

a plurality of blades operatively connected to and configured to selectively rotate around the central hub;

a blade ring fixedly connected to the plurality of blades, the blade ring defining at least one blade ring slot;

a locking device configured to selectively prevent the plurality of blades from rotating, the locking device including a movable member and an actuation device for moving the movable member; and

wherein the movable member is slidable relative to the blade ring between two positions, an unlocked position that substantially permits the plurality of blades to rotate and a locked position that substantially prevents the plurality of blades from rotating.

2. The assembly of claim 1 , further comprising:

an electric motor operatively connected to the central hub for selectively powering the plurality of blades; and

wherein the locking device is configured to selectively prevent the blades from rotating when the plurality of blades are not powered.

3. The assembly of claim 1 , wherein the movable member is movable in a direction substantially perpendicular to a direction of rotation of the blade ring.

4. The assembly of claim 1 , further comprising:

an exterior ring configured to at least partially surround the blade ring and defining an inner opening and an exterior ring aperture;

wherein the blade ring is positioned within the inner opening of the exterior ring; and

wherein the actuation device is positioned within the exterior ring aperture.

5. The assembly of claim 4 , further comprising:

a fan shroud defining an inner perimeter; and

wherein the exterior ring is operatively connected to the inner perimeter of the fan shroud.

6. The assembly of claim 1 , wherein:

the actuation device includes an electromagnet having a ferromagnetic core, the electromagnet defining a powered state and a non-powered state;

the movable member is composed of a permanent magnet and configured to be attracted towards the ferromagnetic core of the electromagnet when the electromagnet is in the non-powered state; and

wherein the movable member is configured to be repelled by an induced magnetic field generated by the electromagnet when the electromagnet is in the powered state.

7. The assembly of claim 6 , further comprising:

a power source operatively connected to the electromagnet; and

a switch operatively connected to the power source and having an open and a closed position; and

wherein the electromagnet is in the powered state when the switch is in the closed position and the electromagnet is in the non-powered state when the switch is in the open position.

8. The assembly of claim 6 , wherein:

the movable member in the unlocked position is positioned in the at least one blade ring slot such that the movable member rotates with the blade ring and the plurality of blades; and

the movable member in the locked position is configured to move away from the at least one blade ring slot.

9. The assembly of claim 6 , further comprising:

a biasing member operatively connected to the movable member and configured to bias the movable member toward the locked position; and

wherein the biasing member is positioned within the at least one blade ring slot of the blade ring.

10. The assembly of claim 9 , wherein the biasing member is an extension spring.

11. The assembly of claim 1 , wherein the actuation device includes:

a stator assembly;

a rotor assembly positioned at least partially within and rotatable within the stator assembly; the rotor assembly having a permanent magnet component;

a nut member rigidly connected to and rotatable with the rotor assembly, the nut member defining an internal threaded portion;

a screw member positioned within the nut member and having an external threaded portion interacting with the internal threaded portion of the nut member; and

wherein a current flowing through the stator assembly is configured to induce motion of the movable member.

12. The assembly of claim 11 , wherein the movable member is operatively connected to the screw member.

13. The assembly of claim 11 , wherein the movable member is integrally formed with the screw member.

14. The assembly of claim 11 , further comprising:

an exterior ring configured to at least partially surround the blade ring and defining an inner opening and an exterior ring aperture;

wherein the blade ring is positioned within the inner opening of the exterior ring; and

wherein the actuation device and the movable member are positioned within the exterior ring aperture.

15. The assembly of claim 11 , wherein:

the movable member in the locked position includes a jutting portion that extends into the at least one blade ring slot, thereby substantially preventing the plurality of blades and blade ring from rotating; and

wherein the jutting portion is configured to slide out of the at least one blade ring slot when the movable member is in the unlocked position.

16. A cooling fan assembly comprising:

a central hub;

a plurality of blades operatively connected to and configured to selectively rotate around the central hub, the plurality of blades each defining respective outermost radial portions;

a blade ring fixedly connected to the respective outermost radial portions of the plurality of blades, the blade ring defining at least one blade ring slot;

a locking device configured to selectively prevent the plurality of blades from rotating, the locking device including a movable member and an actuation device for moving the movable member;

wherein the movable member is slidable relative to the blade ring between two positions, an unlocked position that substantially permits the plurality of blades to rotate and a locked position that substantially prevents the plurality of blades from rotating;

wherein the movable member is movable in a direction substantially perpendicular to a direction of rotation of the blade ring;

wherein the actuation device includes an electromagnet having a ferromagnetic core; and

wherein the movable member is composed of a permanent magnet.

17. The assembly of claim 16 , wherein the ferromagnetic core of the electromagnet is composed of iron.

18. A vehicle comprising:

an engine;

a radiator;

a cooling fan assembly, wherein the assembly includes:

a central hub;

a plurality of blades operatively connected to and configured to selectively rotate around the central hub;

a blade ring fixedly connected to the plurality of blades, the blade ring being annularly-shaped and defining at least one blade ring slot; and

a locking device configured to selectively prevent the plurality of blades from rotating, the locking device including a movable member and an actuation device for moving the movable member;

wherein the movable member is slidable relative to the blade ring between two positions, an unlocked position that substantially permits the plurality of blades to rotate and a locked position that substantially prevents the plurality of blades from rotating; and

wherein the movable member is movable in a direction substantially perpendicular to a direction of rotation of the blade ring.