Electrical connectors – Coupling part to receive fluorescent or neon lamp – With provision for transverse receipt of lamp contact
Reexamination Certificate
2000-01-25
2001-09-18
Sircus, Brian (Department: 2839)
Electrical connectors
Coupling part to receive fluorescent or neon lamp
With provision for transverse receipt of lamp contact
C439S244000
Reexamination Certificate
active
06290522
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is directed to lampholders for electrical lamps, and more particularly to lampholders to mechanically support and provide electrical power to fluorescent lamps.
2. Description of the Prior Art
Originally, fluorescent tube lamps were cylindrical glass enclosures or envelopes which contained an ionizable gas. A tungsten filament located at each of the two tube ends required a low voltage from a ballast or “starter” to heat the filament to incandescence to create thermionic emissions so that enough ions were created to ionize the gas. The voltage from the ballast was applied to the filaments via two metallic lamp pins which extended out of each end of the glass tube envelope. The two lamp pins at each end were engaged by lampholders at each end which provided mechanical support and electrical power to the fluorescent lamps.
Later, fluorescent lamps called “cold cathode” lamps were developed that eliminated the need to heat the filament. Instead, a voltage, in the order of 1300 volts, produced by a high-voltage ballast, was applied to the filament to force a sufficient number of tungsten ions from the filament to ionize the gas for ignition However, since the pins also serve with the lampholders as mechanical supports for the fluorescent lamp, and in view of the large number of installed double-contact fluorescent lampholders, a need for fluorescent lamps with two lamp pins at each end continues to exist. Some manufacturers applied an electrical shunt across the two lamp pins at each lamp end, in the belief that the high energizing voltage would need to be evenly distributed across each of the filaments to cause an even dispersion of ions.
FIGS. 1 and 2
show a prior art fluorescent lampholder
10
and the manner in which it was connected to an electrical source. A body
12
fabricated of phenolic, rubber or a suitable plastic is arranged to be placed in a housing, at the ends of a reflector or other similar mounting (not shown). Body
12
has a channel
14
with an entry slot
16
leading from outside body
12
into channel
14
. Placed in the open back of body
12
are two lamp pin contacts
18
each intended to engage one of the fluorescent tube pins (not shown) in their notches
22
in the upper portion
20
of lamp pin contacts
18
. The lamp pin contacts
18
are assembled to the interior wall of body
12
by fasteners (not shown) extending through an aperture
24
in each of the lamp pin contacts
18
. A shunt bar
26
is coupled between the lamp pin contacts
18
. The bottom portion
28
of lamp pin contacts
18
are bifurcated as at
30
and provide two coupling tongues
32
which make contact with the bared end of an insulated conductor (not shown). Tongues
32
act as one-way clutches allowing the conductor ends to be inserted but not withdrawn while making electrical contact with such bare conductor ends. A cover
34
of insulating material covers the back of the body
12
and is held in place by a staple
36
.
A ballast
40
, coupled to the lines
38
from a 120 Volt AC supply
37
at one end, is coupled to shunt
26
A which spans lamp pin contacts
18
A,
18
B and shunt
26
B which spans lamp pin contacts
18
C,
18
D as shown in FIG.
2
. Within the fluorescent lamp
42
tube, at one end thereof is a filament
44
connected across lamp pin contacts
18
A,
18
B and at the other end is a filament
46
connected across lamp pin contacts
18
C,
18
D.
To use the lampholder
10
, a fluorescent lamp (not shown) would be turned so that its lamp pins at one end are positioned one above the other and the lamp pins made to enter slot
16
and moved towards the bottom of body
12
. Once the lamp pins are aligned with the channel
14
, the lamp is rotated until each of the lamp pins enters the notch
22
of its associated lamp pin contact
18
. The tapered lead-ins to each of the notches
22
from above and below assure that the lamp pins enter the notches
22
. The resilience and shape of the portion
20
allows the portion
20
to be deflected as the lamp pins move into position in the notches
22
and return to grip the lamp pins once they are in their associated notches
22
. A similar lampholder
10
is positioned at the opposite end of the lamp to engage the lamp pins thereat.
With further improvements to the lamp and electronic ballast no filament is needed. Currently, fluorescent lamps are manufactured to work in either a hot cathode mode or a cold cathode mode.
SUMMARY OF THE INVENTION
The instant invention overcomes the difficulties noted above with respect to prior art cold cathode fluorescent lamp lampholders by eliminating the shunt and by eliminating one electrical lamp pin contact in the lampholder while retaining the ability to mechanically support the fluorescent lamp and couple it to a source of AC electrical power. This further negates the belief of evenly dispersed voltage across the filament. To retain the fluorescent lamp in place one of the customary lamp pin contacts is replaced in each of the lampholders with one or more resilient retaining arms to engage one of the fluorescent lamp pins. The other of the two lamp pins is engaged by the notch of an associated lamp pin contact. The resilient retaining arms also insure that the other lamp pin will remain seated in the notch of the lamp pin contact. The retaining arm may be made of an insulating material or fabricated of a material and in a form such that it provides its own spring forces or is provided with suitable spring members. It may also be fabricated of metal strips or metal spring stock to provide the desired spring forces. However, the retaining arm is not connected to a source of AC power.
A compression spring member may also be used to urge an electrical contact member into contact with both of the lamp pins of an inserted fluorescent lamp; This spring member is coupled to a contact to which an electrical conductor may be fastened to provide electrical power to the lamp. The compression spring may be compressed to initially place the lamp in the lampholder and thereafter allowed to expand to maintain the contact between the lamp pins of the lamp and the contact. It is an object of the invention to provide a lampholder for fluorescent lamps.
It is an object of the invention to provide a lampholder for cold cathode fluorescent lamps.
It is an object of the invention to provide a lampholder for cold cathode fluorescent lamps which operate with high-voltage electronic ballasts.
It is still a farther object of the invention to provide a lampholder for cold cathode fluorescent lamps which is simpler and has fewer parts than prior art fluorescent lampholders.
It is yet another object of the invention to provide in one form a lampholder for fluorescent lamps which eliminates the shunt member and replaces one conductive pin engaging assembly with a lamp retaining device which carries no current and in another, uses a spring operated plunger to retain the lamp.
Other objects and features of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principles of the invention, and the best mode which is presently contemplated for carrying them out.
REFERENCES:
patent: 3351884 (1967-11-01), Pistey
patent: 3359414 (1967-12-01), Ege
patent: 3818418 (1974-06-01), Detch
patent: 4994710 (1991-02-01), Roelevink et al.
Campolo Steve
Endres Paul
King Gerald N.
Leviton Manufacturing Co. Inc.
Prasad Chandrika
Sircus Brian
Sutton Paul J.
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