AU1869102A - Ceiling fan - Google Patents

Description

P/00/01 1 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Ceiling fan The following statement is a full description of this invention, including the best method of performing it known to us: Freehills Carter Smith Beadle Melbourne\004003224 Printed 25 February 2002 (12:15) page 2 Freehills Carter Smith Beadle Melbourne\004003224 Printed 25 February 2002 (12:15) page 2 003992137 CEILING FAN Field of the Invention This invention relates to ceiling fans and in particular to electrical ceiling fans that may be safely installed without the need for a qualified electrician.

Background of the Invention A typical ceiling fan includes an upper canopy and ceiling anchorage, a motor and motor housing, blades and blade mountings, and a control enclosure.

The ceiling fan may further include optional items such as a light, a remote control receiver unit, and a decorative outer housing, for example.

10 The motor of the ceiling fan includes a motor shaft about which the motor body rotates. A motor housing surrounds the motor body and is stationary. The motor housing is connected to the lower end of the upper canopy. Due to strength considerations, the motor housing is typically metal. The electrically live parts of the motor are the windings, and these are usually insulated. An air gap between .i 15 the motor and the motor housing provides some insulation between the windings %0:0 00 and the metal motor housing in the event that the windings insulation fails, however, it is possible that the motor housing can become electrically live. To o. guard against this, ceiling fans are conventionally provided with an earth 0 1.: connection.

Due to the above construction of ceiling fans, they typically must be installed by a qualified electrician due to the dangers of electrocution and the need to properly earth the ceiling fan.

It is an object of the invention to provide a ceiling fan that is properly electrically insulated and that can be safely installed without the need for a qualified electrician.

003992137 2 Advantageously, the ceiling fan may be installed by the installer connecting a bayonet cap lampholder adaptor, that is part of the fan assembly, into an existing ceiling mounted bayonet cap lampholder.

Summary of the Invention The invention accordingly provides a ceiling fan having a plurality of blade units, a motor assembly including a motor for rotating the blades, and enclosure means, wherein the ceiling fan includes one or more insulation barriers adjacent the motor assembly for electrically insulating the motor assembly from said blade units and from said enclosure means.

The enclosure means may include an upper canopy, located above and adjacent the motor assembly when the ceiling fan is installed, and an enclosure for the motor. A first said insulation barrier is preferably provided between the motor assembly and the upper canopy and enclosure so as to electrically insulate the S•upper canopy and enclosure from the motor assembly.

The blade units may typically include blade mounting means for respective blades of the ceiling fan, which blade mounting means are attached to a housing of said motor for rotation with the housing. Preferably, a second said insulation barrier is provided between the motor housing and the blade mounting means so .i as to electrically insulate the blade mounting means from the motor housing.

Advantageously, this second insulation barrier includes an electrically insulating moulding separately attached to the motor housing and to the blade mounting means by respective fasteners overlaid by respective insulating rings.

The ceiling fan may additionally include a further enclosure that houses controls of the ceiling fan and/or an associated lamp. This further enclosure is located below and adjacent the motor housing when the ceiling fan is installed, and advantageously includes a further said insulation barrier comprising e.g. an insulating liner.

003992137 3 In an embodiment, the motor assembly includes a shaft fixed at or adjacent its upper end to said first insulation barrier, which barrier carries metal rings to strengthen the mounting in seats defined by the insulation barrier so as electrically isolate the shaft from the enclosure means.

The insulation barriers preferably include moulded thermoplastic components.

Brief Description of the Drawings The invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a part elevational/part axial sectional view of a ceiling fan according to an embodiment of the invention; Figure 2 is a sectioned fragmentary perspective view showing the attachment of the blade units to the motor housing via the second insulation barrier; and Figure 3 is an axial cross-section of the insulation moulding forming part of the second insulation barrier; Description of Preferred Embodiments Figures 1 to 3 illustrate a ceiling fan in accordance with an embodiment of the invention. Several components of the ceiling fan, such as the pull switch 23, are conventional and/or decorative and therefore will not be described in detail.

When installed, the fan is securely attached to the ceiling by a ceiling support frame 2, in a conventional manner. An electrical connection is made to an electrical outlet (not shown), eg. a socket in the ceiling, via an adaptor (not shown). An anti-vibration pad 1 is provided about the anchorage points of frame 2 to the ceiling.

003992137 4 Directly below the ceiling support frame is an upper canopy 4. The upper canopy 4 extends about a peripheral skirt portion 21 of the support frame 2 and is attached at spaced intervals to this skirt by fixing screws 30. Frame 2 and canopy 4 are typically formed from metal due to strength considerations.

Secured to an annular base flange 41 of upper canopy 4 by angularly spaced threaded fasteners 28 is the fan motor enclosure 10, a hollow annular casing having multiple arrays of ventilation holes 101.

Enclosure 10 surrounds and encloses a motor 9, which in turn is rotatably fixed on a hollow vertical shaft 31, co-axial with canopy 4 and enclosure 10 Shaft 31 provides a conduit for electrical wiring (not shown), and is retained in a ."first insulation barrier assembly 50 by threaded nuts 29 that engage a threaded S•upper end portion 311 of shaft 31.

First electrical insulation barrier 50 is in the form of a moulded thermoplastic ring 7. Ring 7 has a central aperture 71 to receive shaft 31 in a close fit, and further defines a flat annular disk 72 and an upstanding tubular partition 73.

:Partition 73 defines, with the upper surface of disk 72, a seat for base flange 41 of canopy 4 and an uppermost inner flange portion 102 of enclosure 10. Fasteners 28 extend through base flange 41, flange portion 102, and disk 72 to threadably engage respective apertures in a lower canopy support ring 8. Partition 73 further defines, within the partition, a seat 76 for an upper canopy support ring 6 that underlies upper shaft nut 29 and its washer 291.

Rings 6, 8 are mild steel rings that co-operate to reinforce the mounting which incorporates insulation barrier 50, while thermoplastic insulation ring 7, by virtue of tubular partition 73, electrically isolates shaft 31 and canopy support ring 6 from canopy 4 and enclosure 10 in the event that the housing of motor 9 and shaft 31 become electrically live. It will further be seen that a further depending tubular portion 74 of insulation ring 7 separates lower canopy support ring 8 from lower nut 29 and shaft 31, and projects below ring 8 closer to the housing 91 of motor 9.

003992137 The blades 100 (Figure 2) of the ceiling fan project from respective blade support brackets 25 to which they are attached by fixings such as screws 26.

Support brackets 25 are made of metal so as to provide adequate strength and support to the blades 100. These blade units 102 including brackets 25 and blades 100 are fixed to the housing 91 of motor 9 so as to rotate, in operation, with the motor about shaft 31. The fixing arrangement is via a second electrical insulation barrier assembly 60 designed to prevent the blades becoming electrically live in the event the motor housing becomes live.

Insulation barrier 60 comprises three principal components: an electrically insulating thermoplastic moulding 12 and respective upper and lower flat rings 11, 13 of like electrically insulating thermoplastic material. As best appreciated from Figure 3, moulding 12 has two sequences of apertures 121, 122, alternatively S•angularly spaced about the moulding. One sequence of apertures 121 receives fasteners 15 from below for attaching the blade support brackets 25 to the 15 moulding and to an intervening metal blade attachment ring 15 of shallow inverted-channel cross-section. The other sequence of apertures 122 receives fasteners (not shown) for securing moulding 12 to motor housing 91. Apertures 121 have rebates 123 for locating the nuts of fasteners 15, and upper insulating ring 11 is accommodated in an outer seat 125 of moulding 12 and thereby covers rebates 123 and insulates fasteners 15 from motor housing 91. Similarly, the nuts of the motor-fixing fasteners are located in rebate 124 of aperture 122 and in turn lower insulating ring 13 covers rebates 124 and electrically insulates these fasteners from the underlying blade attachment rings 15. The four blade support brackets are thereby electrically isolated from the motor housing should it become electrically live.

It will be seen from Figure 1 that insulation moulding 12 tapers on its outer periphery to an outer lip 128 that protrudes within the open lower rim 103 of enclosure 10, without being attached to it. This configuration means that the moulding also ensures against contact between this rim 103 and the motor housing 91.

003992137 6 Secured to the lower threaded end of hollow shaft 31, by fixing nuts 16 and associated washers, is control enclosure 80. Enclosure 80 includes a canopy 81 with an upper flange portion actually retained by nuts 16, an inner bowl-shaped electrically insulating lining 18 of suitable thermoplastic material, an outer cylindrical facing 17, and a base portion 27 fixed within facing 17 by a series of angularly spaced screws 24. Enclosure 80 contains pull switch 23 for the lamp, and base portion 27 mounts lampholder 20 for lamp 22. The lampholder 20 in turn supports a retainer canopy 32 with keeper screws 21 for securing lamp glass or lens 85. Retainer canopy 32 is spaced from base portion 27 by thermal insulating 10 ring 19.

In summary, should motor 9 electrically fail in any way (eg. through failure of the motor windings) and its housing, and/or shaft 31, become electrically live as oo.oo a result, the externally exposed electrically conductive components of the ceiling fan assembly (eg. upper canopy 4, motor enclosure 10, blade support brackets 15 and associated elements, and canopies 27, 32) are prevented from also becoming live by electrical insulation barrier assemblies 50, 60 and enclosure lining 18.

It will be appreciated that, by virtue of the thermoplastic insulation barriers strategically located in the structure of the ceiling fan, earthing of the aforementioned externally exposed components is unnecessary and the ceiling 20 fan may be safely installed without the need for a qualified electrician..

It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

Claims (5)

1. A ceiling fan having a plurality of blade units, a motor assembly including a motor for rotating the blades, and enclosure means, wherein the ceiling fan includes one or more insulation barriers adjacent the motor assembly for electrically insulating the motor assembly from said blade units and from said enclosure means.

2. A ceiling fan according to claim 1, wherein the enclosure means includes an upper canopy, located above and adjacent the motor assembly when the ceiling fan- is installed, and- an enclosure for the motor, and further including one of said 10 insulation barriers between the motor assembly and the upper canopy and enclosure so as to electrically insulate the upper canopy and enclosure from the •motor assembly.

3. A ceiling fan according to claim 1 or 2, wherein the blade units include o blade mounting means for respective blades of the ceiling fan, which blade mounting means are attached to a housing of said motor for rotation with the *housing, and further including one of said insulation barriers provided between the motor housing and the blade mounting means so as to electrically insulate the blade mounting means from the motor housing. S"4. A ceiling fan according to claim 3, wherein the insulation barrier between the motor housing and the blade mounting means includes an electrically insulating moulding separately attached to the motor housing and to the blade mounting means by respective fasteners overlaid by respective insulating rings. A ceiling fan according to any preceding claim, further including a further enclosure, located below and adjacent the motor housing when the ceiling fan is installed, the further enclosure including a further said insulation barrier.

6. A ceiling fan according to claim 5 wherein the further said insulation barrier is an insulating liner.

0039921.37 8 7. A ceiling fan according to claim 2, wherein, the motor assembly includes a shaft fixed at or adjacent its upper end to the one of said insulation barriers, which barrier carries metal rings to strengthen the mounting in seats defined by the insulation barrier so as electrically isolate the shaft from the enclosure means. 8. A ceiling fan according to any preceding claim, wherein the one or more insulation barriers include moulded thermoplastic components. 9. A ceiling fan substantially as herein described with reference to the accompanying drawings. Hagemeyer Electrical Group 10 By its Registered Patent Attorneys S" Freehills Carter Smith Beadle 23 February 2002