Fan blades and associated blade tips

Patent metadata

Field	Value
Publication number	US-9726192-B2
Application number	US-201514675392-A
Country	US
Kind code	B2
Filing date	Mar 31, 2015
Priority date	Mar 31, 2015
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

Fans having fan blades with lightweight blade tips are disclosed herein. In one embodiment, for example, each fan blade includes a blade tip attached to an end portion of a main airfoil. The blade tip includes a shaped body that is molded over a support structure to form the shape and exterior surface of the blade tip.

First claim

We claim:

1. A fan blade tip configured to attach to an end portion of a fan blade, wherein the fan blade tip comprises:
an internal support structure comprising a first material having a first density; and
a shaped body comprising a second material encasing the internal support structure and defining an exterior surface of the fan blade tip, wherein the second material has a second density that is less than the first density, wherein the internal support structure includes a base member and a plurality of elongate support elements projecting outwardly therefrom, wherein the elongate support elements are encased in the second material, and wherein the base member is configured to attach to the end portion of the fan blade.

2. The fan blade tip of claim 1 wherein the elongate support elements project in a first direction, and wherein the base member includes at least one insert portion extending in a second direction generally opposite the first direction and configured to insert into a cavity in the fan blade.

3. The fan blade tip of claim 1 wherein the second material defines the shape of an outer edge of the fan blade tip, and wherein the elongate support elements project toward the outer edge at individual distances configured to complement the shape of the outer edge.

4. The fan blade tip of claim 1 wherein the second material defines a planform of the fan blade tip, and wherein each of the elongate support elements has a length selected to correspond to the planform.

5. The fan blade tip of claim 1 wherein the exterior shape of the shaped body is defined solely by the second material.

6. The fan blade tip of claim 1 wherein the second material comprises a foam material.

7. A fan blade tip configured to attach to an end portion of a fan blade, wherein the fan blade tip comprises:
an internal support structure comprising a first material having a first density; and
a shaped body comprising a second material encasing the internal support structure and defining an exterior surface of the fan blade tip, wherein the second material has a second density that is less than the first density, wherein the internal support structure includes a plurality of cantilevered support elements projecting outwardly from the end portion of the fan blade, and wherein the cantilevered support elements are encased in the second material.

8. The fan blade tip of claim 7 wherein the internal support structure further includes a base member, wherein the plurality of cantilevered support elements project outwardly from the base member, wherein each of the cantilevered support elements includes an exterior surface, and wherein the second material encapsulates and adheres to the entire exterior surface of each of the cantilevered support elements.

9. The fan blade tip of claim 7 wherein the cantilevered support elements are staggered in length.

10. The fan blade tip of claim 7 wherein the second material comprises a foam material.

11. A fan blade tip configured to attach to an end portion of a fan blade, wherein the fan blade tip comprises:
an internal support structure comprising a first material having a first density; and
a shaped body comprising a second material encasing the internal support structure and defining an exterior surface of the fan blade tip, wherein the second material has a second density that is less than the first density, wherein the second material forms an airfoil having an inboard chord and an outboard chord, wherein the inboard chord has a first chord length, wherein the outboard chord has a second chord length less than the first chord length, and wherein the second material decreases in thickness from the inboard chord to the outboard chord.

12. The fan blade tip of claim 11 wherein the second material comprises a foam material.

13. The fan blade tip of claim 11 wherein the second material comprises synthetic foam rubber.

14. The fan blade tip of claim 11 wherein the first density is in the range of from about 20 pounds per cubic foot (pcf) to about 60 pcf, and wherein the second density is in the range of from about 1 pcf to about 20 pcf.

15. The fan blade tip of claim 14 wherein the first material comprises acrylonitrile butadiene styrene (ABS), and the second material comprises polyeurethane foam.

16. A fan blade configured to attach to a central hub of a fan, the fan blade comprising:
a main airfoil having an outboard end portion; and
a blade tip, including—
an internal support structure projecting outwardly from the outboard end portion, wherein the internal support structure includes a plurality of cantilevered support elements, and
a shaped body formed over the plurality of cantilevered support elements and defining an exterior surface of the blade tip, wherein the internal support structure comprises a molded plastic, and the shaped body comprises a foam material encasing the molded plastic.

17. The fan blade of claim 16 wherein the internal support structure includes at least one insert portion configured to insert into the main airfoil.

18. A fan blade configured to attach to a central hub of a fan, the fan blade comprising:
a main airfoil having an outboard end portion; and
a blade tip, including—
an internal support structure projecting outwardly from the outboard end portion, wherein the internal support structure includes a plurality of cantilevered support elements, and
a shaped body formed over the plurality of cantilevered support elements and defining an exterior surface of the blade tip, wherein the shaped body has a planform shape of the blade tip, and wherein the cantilevered support elements are staggered in length such that they complement the planform shape.

19. The fan blade of claim 18 wherein the internal support structure comprises a first material, and the shaped body portion comprises a second material that is different than the first material.

20. The fan blade of claim 18 wherein the main airfoil includes an outer wall and an internal web separating a leading edge cavity from a trailing edge cavity, wherein internal support structure further includes a first insert portion configured to insert into the leading edge cavity, and a second insert portion configured to insert into the trailing edge cavity.

21. The fan blade of claim 20 wherein internal support structure further includes an abutment feature, wherein the first and second insert portions project from the abutment feature in a first direction, and wherein the cantilevered support elements project from the abutment feature in a second direction generally opposite the first direction.

22. A fan comprising a plurality of blades extending outwardly from a central hub configured to be suspended from a ceiling or other elevated structure, wherein each of the blades includes:
a main airfoil having an inboard end portion disposed toward the central hub and an outboard end portion spaced apart from the central hub; and
a blade tip attached to the outboard end portion of the main airfoil, wherein the blade lip includes—
an internal support structure, and
means for defining an exterior surface of the blade tip and its overall shape, wherein the means for defining encapsulates the internal support structure, and wherein the internal support structure includes a plurality of coplanar, elongate support elements that extend at least partially into the means for defining.

23. The fan of claim 22 , wherein the internal support structure further includ

Assignees

• Assa Abloy Entrance Systems Ab

Inventors

• Whitley L Blake
• Hoofard Richard K

Classifications

• F05D2300/612

  Foam · CPC title

• F05D2240/307

  related to the tip of a rotor blade · CPC title

• F04D29/34

  Blade mountings {(for axial flow compressors F04D29/322)} · CPC title

• F04D29/325

  for axial flow fans (blade mountings F04D29/34, blades F04D29/38) · CPC title

• F04D25/088

  Ceiling fans · CPC title