Fan with collapsible blades, redundant fan system, and related method

• US 20040101406A1
• Filed: 11/27/2002
• Published: 05/27/2004
• Est. Priority Date: 11/27/2002
• Status: Active Grant

• Current Assignee: Nidec America Corporation (Nidec Corporation)
• Original Assignee: Nidec America Corporation (Nidec Corporation)
• Inventors: Hoover, John
• Granted Patent: US 6,860,713 B2
• Time in Patent Office: Days
• US Class Current: 416/140
• CPC Class Codes: F01D 5/00 Blades; Blade-carrying members nozzle boxes F01D9/02; Heating, heat-insulating, cooling or antivibration means on the blades or the members special arrangements in rotors dealing with breaking off of part thereof F01D21/045
• CPC Class Codes: F04D 19/007 multistage fans
• CPC Class Codes: F04D 27/008 Stop safety or alarm devices, e.g. stop-and-go control; Disposition of check-valves
• CPC Class Codes: F04D 29/362 during rotation
• CPC Class Codes: F04D 29/382 Flexible blades
• CPC Class Codes: F05B 2240/202 with adjustable area of intercepted fluid
• CPC Class Codes: F05D 2270/11 to prolong engine life
• CPC Class Codes: G06F 1/20 Cooling means
• CPC Class Codes: H05K 7/20172 Fan mounting or fan specifications
• CPC Class Codes: H05K 7/2019 Fan safe systems, e.g. mechanical devices for non stop cooling
• CPC Class Codes: H05K 7/20718 Forced ventilation of a gaseous coolant in closed loop H05K7/20754

Abstract

A redundant fan system for a computer includes two fans installed in series with at least one of the fans having collapsible blades. A fan system of this type reduces the fan inefficiency caused when one fan in a series mounted pair is not operating, either because it is free-wheeling or in a locked rotor condition. When non-operational, the fan blades of the collapsible fan fold inward due to airflow generated by the operational fan over the collapsible blades. The ability of the blades to fold reduces the inefficiency of the operational fan, having less of an effect on fan life. Also, because the flow of air is less restricted, proper airflow can be maintained, thus preventing overheating of the computer.

Claims

1. A collapsible fan for use in a redundant fan system comprising a first fan including a fan frame, a rotor rotatably mounted on the fan frame, a first aperture located on one side of the rotor, a second aperture located on an opposite side of the rotor relative to the first aperture, and a plurality of fan blades mounted on the rotor, the collapsible fan comprising:

a fan frame, a rotor rotatably mounted on the fan frame, a first aperture located on one side of the rotor, a second aperture located on an opposite side of the rotor relative to the first aperture, and a plurality of collapsible fan blades pivotally mounted on the rotor, wherein the collapsible fan is mountable adjacent to one of the first and second apertures of the first fan, and the collapsible fan blades are collapsible onto the respective rotor upon rotating the first fan rotor.

2. The collapsible fan set forth in claim 1, further comprising a sensor for sensing a failure of the collapsible fan.

3. The collapsible fan set forth in claim 2, further comprising:

a controller coupled to the sensor for energizing the first fan in response to a failure of the collapsible fan to, in turn, collapse the plurality of collapsible blades.

4. The collapsible fan set forth in claim 2, wherein the sensor is selected from the group including a vane switch, a locked rotor signal, a pressure sensor, and a temperature gauge.

5. The collapsible fan set forth in claim 1, wherein the plurality of collapsible blades collapse due to an airflow generated by the first fan.

6. The collapsible fan set forth in claim 1, wherein the plurality of collapsible blades are opened and maintained in the open position in response to centrifugal force generated by rotation of the rotor.

7. The collapsible fan set forth in claim 1, wherein the plurality of collapsible blades are connected to the rotor at an angle oblique to the axis of the rotor.

8. The collapsible fan set forth in claim 1, further comprising a plurality of pivot connectors that pivotally connect a plurality of collapsible blades to the rotor.

9. The collapsible fan set forth in claim 8, wherein the rotor includes a plurality of pivot mounts angularly spaced relative to each other, and each pivot connector includes a pivot pin received within the respective pivot mount for pivotally connecting a respective blade to the rotor.

10. The collapsible fan set forth in claim 9, wherein each pivot mount includes a recess, and each pivot pin is frictionally engaged within the respective recess to secure the respective blade to the blade mount.

11. The collapsible fan set forth in claim 1, wherein the fan is a brushless dc fan.

12. The collapsible fan set forth in claim 1, wherein a plurality of the collapsible fan blades angularly overlap one another.

13. The collapsible fan of claim 1 in combination with a redundant fan system, comprising:

a first fan including a fan frame, a rotor rotatably mounted on the fan frame, a first aperture located on one side of the rotor, a second aperture located on an opposite side of the rotor relative to the first aperture, and a plurality of fan blades mounted on the rotor; and

wherein the collapsible fan forms a second fan mounted adjacent to one of the first and second apertures of the first fan, and the collapsible fan blades of the second fan are collapsible onto the respective rotor upon rotating the first fan rotor.

14. The redundant fan system set forth in claim 13, further comprising a frame for mounting the first fan and second fan.

15. The redundant fan system set forth in claim 13, further comprising:

an enclosure having at least one outer wall, the enclosure defining an interior and defining an opening in the at least one outer wall, and wherein the first fan is located within the enclosure adjacent to the opening in the at least one outer wall.

16. The redundant fan system set forth in claim 15, wherein the enclosure is a computer housing.

17. The redundant fan system set forth in claim 13, wherein both the first fan blades and second fan blades are collapsible.

18. A collapsible fan for use in a redundant fan system comprising a first fan including a fan frame, a rotor rotatably mounted on the fan frame, a first aperture located on one side of the rotor, a second aperture located on an opposite side of the rotor relative to the first aperture, and a plurality of fan blades mounted on the rotor, the collapsible fan comprising:

a fan including a fan frame, a rotor rotatably mounted on the fan frame, a first aperture located on one side of the rotor, a second aperture located on an opposite side of the rotor relative to the first aperture, and a plurality of fan blades mounted on the rotor; and

means for collapsing the fan blades toward the rotor upon rotating the rotor of the first fan.

19. The collapsible fan set forth in claim 18, wherein a plurality of the collapsible fan blades angularly overlap one another.

20. The collapsible fan set forth in claim 18, wherein the means for collapsing is defined by a plurality of pivot connectors, and each pivot connector pivotally connects a respective fan blade to the rotor.

21. The collapsible fan set forth in claim 20, wherein each pivot connector includes at least one mounting surface on one of the rotor and the blade, and at least one pivot pin on the other of the rotor and the blade that is retained on the mounting surface.

22. The collapsible fan set forth in claim 18, further comprising:

first means for energizing the first fan in response to a failure of the collapsible fan to, in turn, collapse the plurality of collapsible blades of the failed collapsible fan; and

second means coupled to the first means for sensing a failure of the collapsible fan.

23. The collapsible fan set forth in claim 22, wherein the second means is selected from the group including a vane switch, a locked rotor signal, a pressure sensor, and a temperature gauge.

24. The collapsible fan of claim 18 in combination with a redundant fan system, comprising:

a first fan including a fan frame, a rotor rotatably mounted on the fan frame, a first aperture located on one side of the rotor, a second aperture located on an opposite side of the rotor relative to the first aperture, and a plurality of fan blades mounted on the rotor.

25. The redundant fan system set forth in claim 24, in combination with a computer defining a housing and a plurality of computer components mounted within the housing, and wherein the redundant fan system is mounted on the housing for cooling the components within the housing.

26. The redundant fan system set forth in claim 24, wherein the two fans are substantially axially aligned with each other.

27. A method of providing redundant airflow comprising the steps of:

providing a first fan including a plurality of collapsible fan blades;

providing a second fan adjacent to the first fan; and

activating the second fan upon a failure of the first fan and, in turn, moving air with the second fan and collapsing the blades of the first fan.

28. The method set forth in claim 27, further comprising the step of sensing the failure of the first fan, and activating the second fan upon sensing the failure of the first fan.

29. The method set forth in claim 27, further comprising the step of mounting the first and second fans in approximate axial alignment with each other.

30. The method set forth in claim 27, further comprising the step of mounting at least one of the first and second fans within a computer housing.