Background of the Invention
1. Field of Invention
The present invention relates to suspended ceilings having easily installable, removable and/or relocatable lighting means.
2. Description of Prior Art
Due to requirements of the National Electrical Code, lighting fixtures in suspended ceilings, as such fixtures are presently constituted, have to be wired-in by way of conduited or armored cable. As a result, the fixtures are not only difficult and highly time-consuming to install, but--once installed--they are also very difficult and time-consuming to remove and/or relocate. Moreover, their installation, removal and/or relocation require the services of a licensed electrician.
No method presently exists whereby such lighting fixtures can be safely and conveniently installed, removed and/or relocated, without requiring the use of conduited or armored cable, and without requiring the services of a licensed electrician.
Summary of the Invention
Motivation and Rationale Underlying the Invention
The general motivation underlying the present invention derives from a fundamental insight to the effect that it appears feasible to provide for a cost-effective arrangement whereby lighting fixtures in a suspended ceiling can be safely and conveniently installed, removed and/or relocated by a person of but ordinary skills, and without requiring the services of a licensed electrician.
More specifically and as follows, the motivation and rationale comprises several individual perceptions.
(i) A first perception suggests that, if only the lighting fixtures could be powered from below the suspended ceiling, rather than from the air plenum space above, it would not be necessary to power the fixtures by way of conduited or armored cables. In fact, it would then be permissible, according to normal practices under the National Electrical Code, to provide power to each fixture by way of an ordinary flexible power cord with a plug--with this plug being plugged into an ordinary electrical outlet. Thus, if fixtures were to be installed in a suspended ceiling in this fashion, anyone of but ordinary skills could install, remove and/or relocate them.
Of course, having power cords hanging down from the lighting fixtures in a suspended ceiling would not in most applications represent an attractive proposition, and can not realistically be considered as a generally acceptable alternative to the presently used method of installation based on using conduits and/or armored cable.
(ii) A second perception suggests that by providing, along the underside of the suspended ceiling, a grid of power tracks of the type normally used with track lighting systems, and by providing fixtures with relatively short power cords protruding from the front of the fixtures, it is possible to power each fixture by way of plugging its power cord into a nearby power track and to thereby avoid the problem of power cords hanging down from the lighting fixtures. This arrangement would indeed provide for a simplification of the installation, removal and/or relocation of the lighting fixtures.
Never-the-less, the power cords with their plugs--even if made quite short and light-of-weight--would be quite visible and would probably be objectionable from an aesthetics viewpoint.
(iii) A third perception suggests that it is possible to provide a substantially non-visible electrical connection between the front part of a lighting fixture and an immediately adjacent power track: such connection being accomplished by way of a special power plug protruding through a side-opening near the bottom edge of a fixture and plugged directly into a side-located receptacle slot of the adjacent power track.
(iv) A fourth perception suggests that by making the power tracks of smaller than normal size, which is uniquely permissible in this particular situation since the tracks do not have to support any significant weight, and by integrating these smaller power tracks directly with the suspension grid of the suspended ceiling, it is possible to make the power tracks substantially non-visible; which, in effect, implies that it is possible to provide for a suspended ceiling that has the appearance of an ordinary suspended ceiling--without any conspicuous protrusions or other aesthetically non-acceptable features.
Consequently, it is indeed possible to provide for a suspended ceiling system in which the lighting fixtures can be safely and conveniently installed, removed and/or relocated by a person of but ordinary skills--without requiring the services of a licensed electrician. In fact, the lighting fixtures have been made into plug-in portable lighting means, with all the electrical distributions and connections being made below the air plenum space above the suspended ceiling.
(v) A fifth perception suggests that, by substantially reducing their weight, it is possible to make the lighting fixtures even safer and more convenient to install, remove and/or relocate.
In case of fluorescent lighting fixtures, which are by far the most commonly used lighting fixtures in suspended ceilings, substantial fixture weight reduction may be obtained by way of powering the fixtures with a voltage of relatively high frequency. That way, the requisite fluorescent lamp ballasts can be grossly reduced in weight; which implies that the weight of the complete fixture can be reduced by a substantial factor as well.
Brief Description of the Preferred Embodiment
In its preferred embodiment, subject invention constitutes a modular suspended ceiling integrally combined with a fluorescent lighting system, and comprises the following key component parts and characteristics.
(a) A central power conditioner is mounted on the wall or on the ceiling in some convenient location above the plane of the suspended ceiling. This power conditioner is hard-wireconnected with the electric utility power line and provides a high-frequency voltage output of 120 Volt/30 kHz.
(b) A master power track extends around the periphery of the suspended ceiling. This master power track is hard-wireconnected with the 120 Volt/30 kHz output of the central power conditioner and serves not only as a master power track providing a 120 Volt/30 kHz voltage at its receptacle slots, but also serves as the L-bar ordinarily used along the periphery of a suspended ceiling for supporting the ceiling panels used therein. This combination master power track and L-bar is hereinafter referred to as the L-bar-track.
(c) A suspension grid consisting of substantially ordinary T-bars with light-weight power tracks fastened onto their bottom sides is suspended in the area enclosed by the L-bar-track. The combination T-bars and light-weight power tracks are hereinafter referred to as T-bar-tracks; and these T-bar-tracks are mechanically and electrically plug-in-connected with one another, as well as with the L-bar-track, in such a way as to form a complete modular suspension and power grid for a suspended ceiling and its associated lighting means.
The power tracks fastened onto the bottom of the T-bars have receptacle slots on their sides--but may also have receptacle slots on their bottom sides, in the usual fashion.
(d) Light-weight fluorescent lighting fixtures with high-frequency ballast means are positioned in and supported by the suspension grid structure at the various locations where light is desired. Each fixture has plug-in power input means located at its side, near its bottom edge, and is electrically connected with an adjacent T-bar-track by way of having its side-located plug means plugged into the T-bar-track's side-located receptacle slot.
(e) Ceiling panels are positioned in the suspension grid structure in each place where there is no lighting fixture. These ceiling panels have grooves along their edges, thereby providing for their undersides to be positioned in a flush relationship with the undersides of the T-bar-tracks.
(f) Thus, only the central power conditioner and the L-bar-track have to be installed in conventional hard-wired fashion; which installation probably requires the services of a licensed electrician.
(g) On the other hand, the T-bar-tracks as well as the lighting fixtures, may safely and conveniently be installed, removed and/or relocated in plug-and-receptacle fashion by any person of but ordinary skills--without requiring the services of a licensed electrician.
Brief Description of the Drawing
FIG. 1 provides an overall view of a modular suspended ceiling and lighting system in accordance with the preferred embodiment of the present invention.
FIG. 2 provides details in respect to how a fluorescent lighting fixture is placed into the grid structure and connected with an adjacent T-bar-track.
FIG. 3 provides details in respect to how a T-bar-track is plug-in-connected with an L-bar-track and/or with another T-bar-track.
Detailed Description of the Preferred Embodiment
Details of Construction
In FIG. 1, central frequency converter CFC is mounted on wall W and connected with the power line by armored conductor means ACM. An L-bar-track LBT is mounted on the wall along the periphery of suspended ceiling SC; and T-bar-tracks TBT's are mounted in contact with the L-bar-track and, by way of suspension means SM, in suspended relationship with permanent ceiling PC.
Ceiling panels CP's and special fluorescent lighting fixtures SFLF's are placed into the suspended grid network formed by the L-bar-track and the T-bar-tracks.
FIG. 2 shows salient details in respect to how the ceiling panels and the special fluorescent lighting fixtures are mounted in relationship with the T-bar-tracks. More particularly, FIG. 2 shows a cross-sectional view of a T-bar-track TBT, part of a ceiling panel CP, and part of a special fluorescent lighting fixture SFLF.
Special fluorescent lighting fixture SFLF contains highfrequency ballast means HFBM suitable for powering fluorescent lamp FL from high-frequency voltage obtained by way of flexible conductor means FCM and plug means PM; which plug means is plugged into receptacle slot means RSM of T-bar-track TBT by way of a plug opening PO in the lower side of fixture body FB. A light-transmitting cover means LTCM is fastened onto the fixture body FB in such fashion as to cover the fixture's aperture.
T-bar-track TBT consists of a substantially regular T-bar RTB onto which is cemented or otherwise attached a relatively light-of-weight power track LWPT with track conductors TC.
FIG. 3a shows salient details in respect to how the T-bar-tracks are electrically and mechanically connected with the L-bar-track LBT, as well as how these T-bar-tracks are connected with one another. More particularly, FIG. 3b shows how a plug-in end-prong EP is provided at one end of each T-bar-track TBT. This end-prong is adapted to plug and/or slide into the master receptacle slot MRS of the L-bar-track LBT (see FIG. 3c). Also, a plug-into end receptacle slot ERS is provided at one end of each T-bar-track, which end receptacle slot is adapted to receive and hold the end-prong of another T-bar-track.
Description of Operation
The operation of the above-described modular suspended ceiling and lighting system may be explained as follows.
In FIG. 1, the central frequency converter CFC is powered from the power line and provides an output of 120 Volt/30 kHz voltage, which voltage is applied to a set of track conductors in the L-bar-track LBT.
The 120 Volt/30 kHz voltage on the track conductors in the L-bar-track is provided to the track conductors on each of the T-bar-tracks plugged thereinto. Thus, a complete suspension and track power grid is constructed by plugging suspended T-bar-tracks into the L-bar-track as well as into each other, and the 120 Volt/30 kHz voltage beomes available adjacently to each and every lighting fixture.
After each lighting fixture has been placed into its desired position in the suspended grid structure, electrical connection is made by way of the fixture's side-located plug opening (PO). Through that opening, the ballast plug (PM) is plugged into the adjacent T-bar-track's receptacle slot, thereby providing 120 Volt/30 kHz power to the ballast. After the electrical connection is completed and fluorescent lamps installed, the fixture's light-transmitting cover means (LTCM) is put in place.
In respect to FIG. 2, it should particularly be noted that all the conductor and connector means carrying the 120 Volt/30 kHz power are located outside of the air plenum space (which is the air space between the permanent ceiling and the suspended ceiling). Thus, in effect, each one of the fixtures may be treated as a portable lamp.
The 120 Volt/30 kHz output of the central power conditioner is electrically isolated from the power line; which therefore permits the power distribution to be done without an accompanying ground wire. However, if power-line-isolation is not provided, grounding means would have to be provided; which grounding means could then be furnished in the form of a third conductor in the L-bar-track and in the T-bar-tracks--or, it could be accomplished by using the L-bar and T-bars themselves as ground conductors.
Additional Comments
It is noted that the power distribution system and lighting system described hereinabove is not in any way limited to using high frequency voltage on the L-bar-track and the T-bar-tracks. In fact, regular 120 Volt/60 Hz could readily be used; but then, of course, the weight of the fixtures would have to be higher. On the other hand, in a number of situations, it may prove advantageous to provide DC voltage on the tracks; and then to use an inverter-type ballast in each lighting fixture. In this latter case, however, the fixtures could still be of low weight.
It is also noted that subject power distribution and lighting system may be installed on a retro-fit basis. The master power track could be fastened onto the existing L-bar; and the individual grid power tracks could be fastened onto the existing T-bars.
Then, it is noted that the L-bar-track could readily consist of a central short section of L-bar-track, with additional sections of L-bar-tracks available for plug-in connection with this central L-bar-track, as well as with one another.
Another thing to note is the fact that it is not necessary that every T-bar in the suspended ceiling system grid be a carrier of electric power. For instance, it would be sufficient if only the T-bars in one of the directions carry electric power.
It is anticipated that the various L-bar-tracks and/or the T-bar-tracks be provided in various standard lengths, thereby facilitating easy installation.
In installations of relatively large suspended ceilings it will be necessary to use a plurality of central power conditioners; and, of course, it is then necessary that the outputs from the different power conditioners be treated as separate electrical circuits.
It is also anticipated that the T-bar-tracks be furnished with bottom-positioned receptacle slots--in addition to and/or instead of the side-positioned receptacle slots indicated in FIG. 1. That way, by using special light-of-weight lighting units designed to operate on 120 Volt/30 kHz power, the T-bar-tracks may be used as ordinary power tracks in the sense of constituting power tracks for more-or-less conventional track lighting means. For instance, it is anticipated that low-voltage reflector-type miniature Halogen lamps be conveniently used with these light-of-weight T-bar-tracks--requiring only very light-of-weight voltage transformers to produce the requisite low-magnitude lamp operating voltage from the 120 Volt/30 kHz T-bar-track voltage.
Of course, it is not a basic necessity that the lighting fixtures in subject suspended ceiling and lighting system be of the fluorescent type. On the contrary, it is anticipated that the lighting fixtures be of any desired type, be it fluorescent, incandescent (in which case it would not necessarily be advantageous to provide power in the form of 120 Volt/30 kHz), H.I.D., low-voltage Halogen, etc.
Then, it is also noted that more-or-less ordinary power tracks for a track lighting system may be positioned in nearly any-which-direction on the susended ceiling; and that these power tracks may be powered by way of plug-in-connection with nearby T-bar-tracks.
NATIONAL ELECTRICAL CODE 1984, published by NATIONAL FIRE PROTECTION ASSOCIATION of Quincy, Mass., is herewith by reference incorporated into this specification.
The central frequency converter (CFC) could as well have been mounted below the suspended ceiling. However, by having it enclosed in fire-proof casing, and by having its connecting conductors similarly protected (as in conduits), it is permissible to mount it within the air plenum space.
The term Air Plenum or Air Plenum Space refers to the air space between the suspended ceiling and the permanent ceiling thereabove--this air space being separated from the air space below the suspended ceiling by way of the ceiling panels and the lighting fixtures mounted in the grid openings formed between the T-bar-tracks and the L-bar-tracks.
It is believed that the present invention and its several attendant advantages and features will be understood from the preceeding description. However, without departing from the spirit of the invention, changes may be made in its form and in the construction and interrelationships of its component parts, the form herein presented merely representing the presently preferred embodiment.