FAN BLADE IRON ISOLATION
A ceiling fan is disclosed having an electric motor (13) with a bottom mounting plate (14) to which an annular array of blade irons (16) are coupled, each having a blade (17) mounted thereto. Each blade iron has a motor mounting flange (21) with a recess (23), an end tongue section (26), and an end groove section (27) configured to receive the end tongue section. The end groove section includes an alignment pin (28) and a threaded mounting hole (29). The end tongue section includes an alignment hole (30) configured to receive the groove section alignment pin, and a countersunk hole (31) which is aligned with a mounting hole in the blade iron groove section. A threaded mounting screw (32) is passed through countersunk hole (31) and into mounting hole (29). Each mounting flange is coupled to its two adjacent mounting flanges to provide limited movement therebetween.
This invention relates to a fan system for mounting blade irons and blades, and specifically to systems for isolation of the blades of a ceiling fan from vibrations of the drive motor.
BACKGROUND OF THE INVENTIONMany different types of fans exist today, such as ceiling fans, table fans, pedestal fans, and fans used in conjunction with mechanical equipment. Most of these fans include a blade and a blade mount or blade iron which couples the blade to the motor.
Electrically powered ceiling fans typically have a motor mounted within a stationary housing that is suspended from a ceiling. In operation, the motor rotates an annular array of individual extensions in the form of blade mounts or blade irons. Each blade iron is associated with a blade mounted thereto.
The blades of ceiling fans are usually coupled to the blade irons by passing mounting screws through holes in the blade and into threaded holes in the blade iron. The blade irons are then mounted to the motor.
Ceiling fans are particularly susceptible to the transmission of motor-induced noises since by reason of their large area and length, the blades tend to act as resonating or sound transmitting devices, and thus tend to impart into the air, as noise, vibrations or the like which the blades receive from the drive motor. The drive motors themselves, while relatively quiet by themselves, nevertheless when used to drive ceiling fan blades can impart objectionable noises to the surrounding atmosphere through the blades. Thus, a noisy stator caused for example by slightly loose stator laminations, which would produce an otherwise relatively unobjectionable and unnoticeable stator hum, may at times be transmitted through the motor structure through the blade-mounting cage or rotor to the blades themselves and produce an objectionably loud noise. Similarly, rotor vibrations or noises and bearing noises may be amplified by the blades and become objectionable.
Accordingly, it is seen that a need remains for a ceiling fan system that can restrict the transmission of noise to the rotating blades. It is to the provision of such therefore that the present invention is primarily directed.
SUMMARY OF THE INVENTIONIn a preferred form of the invention a fan comprises an electric motor, an annular array of blade irons, and a ceiling fan blade associated with each blade iron of the annular array of blade irons. Each blade iron has at least one mounting hole therein and an elastomeric grommet positioned within the mounting hole. Each blade iron of the array of blade irons is coupled to two oppositely disposed other blade irons of the array of blade irons.
With reference next to the drawings, there is shown a ceiling fan 10 having an electric motor 13 connected to a source of electric power by unshown wires. The motor 13 includes a bottom mounting plate 14 coupled to the rotor so that it rotates during operation of the motor. The motor bottom mounting plate 14 has an annular array of threaded mounting holes 19. The ceiling fan 10 also includes an annular array of blade irons 16 coupled to the mounting plate 14, each having a blade 17 mounted thereto in conventional fashion.
Each blade iron 16 has a motor mounting flange 21 configured to be coupled with the bottom mounting plate 14 of the electric motor 13. Each mounting flange 21 has a depression or recess 23 extending from the bottom surface 24 and inward surface 25, an end tongue section 26, and an end groove section 27 configured to receive the end tongue section 26. The end groove section 27 includes an alignment pin 28 and a threaded mounting hole 29. The end tongue section 26 includes an alignment hole 30 configured to receive the groove section alignment pin 28, and a countersunk hole 31 which is aligned with mounting hole 29. A threaded mounting screw 32 is passed through tongue section countersunk hole 31 and threaded into groove section mounting hole 29. As such, each mounting flange 21 is coupled to its two oppositely disposed and adjacent mounting flanges 21 with the tongue and groove sections providing limited movement therebetween. The recess 23 extends from the bottom surface 24 less than the full thickness of the mounting flange and thus leaves a relatively thin section 35 of the flange. The recess 23 also includes a semi-circular inwardly opening aperture or slot 38, which interrupts the inward surface 25 at a relatively narrow throat 39. The slot 38 is generally aligned with the threaded mounting hole 19 of the bottom mounting plate 14.
An elastomeric isolation means, in the form of a rubber grommet 40, is configured to be received substantially within the recess 23 and particularly supported on the thin sections 35 within the slot 38. The grommets 40 have a generally cubic shape and are provided with an internal clearance opening 42 which extends axially therethrough. The side walls of the grommet 40 are provided with opposed outwardly opening grooves 44, which grooves are proportioned to receive the sections 35 of the mounting flange, at the slots 38, when the grommet is pressed into place and seated in the recess 23. When the grommet is thus seated, a portion of the grommet extends below the section 35 into the recess 23, but the axial thickness of the grommet 40 is such that the portion which extends into the recess is fully contained within the recess. Another portion of the grommet 40 extends above the upper surface of the mounting flange when the grommet is inserted. The narrow throat 39 tends to retain the grommet in place.
The opening 42 in the grommet is adapted to receive drive means in the form of a threaded headed stud 50. The stud 50 is only partially threaded at its outer end 52. The threads are intended to be received in one of the mounting holes 19 of the mounting plate 14. The stud 50 extends into the mounting plate only to a predetermined depth defined by the depth of the threads 52, and when the same are inserted through the grommet openings 42, the mounting flanges 21 are suspended below the mounting plate on the enlarged heads 51 of the studs 50. The grommets 40 preferably are not drawn into direct contact with the mounting plate 14.
The grommets 40 provides means together with the stud 50 for suspending the blade irons 16 from the motor mounting plate 14, thereby eliminating a metal-to-metal contact. The entire weight of the fan blade 17 and blade irons 16 is carried on the studs 50 through the resilient coupling defined by the grommets 40. The enlarged head 51 of the stud is received adjacent the outer surface of the grommet 40, and thus the weight of the blade irons and blades normally is transmitted to the heads fo the studs through the grommets 40. The connected blade irons with the captured grommets 40 is free to slide slightly up and down on the threaded studs. The purpose of the slight axial freedom of movement is to provide full isolation of the blade irons from the mounting plate 14.
It should be understood that the invention provides an elastomeric attachment, free of any direct metal-to-metal contact, between the blade irons 16 and the motor mounting plate 14. Any vibrations in the motor will tend to be absorbed in the grommets 40, thereby effectively isolating the blades 17 from the effects of such direct transmission of vibration.
It should be understood that the current invention is not intended to be limited to ceiling fans and may apply equally to all types of fans. It should also be understood that the current invention is not limited to a certain number of blades or blade irons.
It thus is seen that a ceiling fan is now provided which isolates motor noises and vibrations in a fan. While this invention has been described in detail with particular references to the preferred embodiments thereof, it should be understood that many modifications, additions and deletions, in addition to those expressly recited, may be made thereto without departure from the spirit and scope of the invention as set forth in the following claims.
Claims
1. A fan comprising,
- an electric motor;
- an annular array of blade irons, each blade iron having at least one mounting hole therein and an elastomeric grommet positioned within said mounting hole, each blade iron of said array of blade irons being coupled to two oppositely disposed other blade irons of said array of blade irons; and
- a ceiling fan blade associated with each said blade iron of said annular array of blade irons.
2. The fan of claim 1 wherein each said blade iron includes a mounting flange having a first end and a second end opposite said first end configured to mate with said first end of another said blade iron of said array of blade irons,
- whereby said first end of one blade iron is coupled to the second end of an adjacent blade iron.
3. The fan of claim 2 wherein said first end is coupled to said second end of another blade iron through a mounting screw.
4. The fan of claim 3 wherein said first end includes an alignment pin and said second end includes an alignment hole configured to receive said alignment pin of another blade iron of said array of blade irons.
5. A fan comprising,
- an electric motor;
- an annular array of blade irons, each blade iron having at least one mounting hole therein and an elastomeric grommet positioned within said mounting hole, each blade iron of said array of blade irons having a mounting flange, each blade iron mounting flange of said array of blade iron being coupled to a pair of adjacent mounting flange so as to form a ring; and
- a ceiling fan blade associated with each said blade iron of said annular array of blade irons.
6. The fan of claim 5 wherein each said blade iron mounting flange includes a first end and a second end opposite said first end configured to mate with said first end of another said blade iron of said array of blade irons,
- whereby said first end of one blade iron is coupled to the second end of an adjacent blade iron.
7. The fan of claim 6 wherein said first end is coupled to said second end of another blade iron through a mounting screw.
8. The fan of claim 7 wherein said first end includes an alignment pin and said second end includes an alignment hole configured to receive said alignment pin of another blade iron of said array of blade irons.
9. A fan comprising,
- an electric motor;
- a plurality of blade irons, each said blade iron having a mounting flange having a first end and a second end, said first end of one said blade iron being coupled to said second end of another said blade iron of said plurality of blade irons, and a elastomeric member positioned between said mounting flanges of said plurality of blade irons and said electric motor; and
- a ceiling fan blade associated with each said blade iron of said annular array of blade irons.
10. The fan of claim 9 wherein said first end is coupled to said second end of another blade iron through a mounting screw.
11. The fan of claim 10 wherein said first end includes an alignment pin and said second end includes an alignment hole configured to receive said alignment pin of another blade iron of said array of blade irons.
12. The fan of claim 9 wherein said mounting flange includes at least one mounting hole therein and wherein said elastomeric member is an elastomeric grommet positioned within said mounting hole
Type: Application
Filed: Mar 26, 2008
Publication Date: Oct 1, 2009
Inventor: Anthony Todd Richardson (Prattville, AL)
Application Number: 12/055,998
International Classification: F01D 5/30 (20060101);
