Electricity: electrical systems and devices – Safety and protection of systems and devices – High voltage dissipation
Reexamination Certificate
1999-06-22
2001-07-10
Sherry, Michael J. (Department: 2836)
Electricity: electrical systems and devices
Safety and protection of systems and devices
High voltage dissipation
C361S118000
Reexamination Certificate
active
06259590
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to protection devices for use with telecommunications equipment, and particularly to devices for protecting telecommunications equipment from potentially damaging current and voltage surges.
2. Description of the Related Art
Grounding mechanisms or devices are designed to protect telecommunications equipment from current surges and voltage surges by providing a grounding path in the event that either such event occurs. Grounding is necessary to prevent current and voltage surges from reaching and damaging fragile telecommunications equipment. Voltage surges typically result from lightning strikes which can generate voltages on the order of 20,000 volts.
A known solid state grounding device or protector
10
is depicted in
FIGS. 1 and 2
. The grounding protector
10
serves as an interface between an electronic module
12
having one or more diodes for connecting a tip wire
14
and a ring wire
16
to ground to allow the discharge of damaging voltage and current surges. The device
10
includes a pair of current sensors in the form of heat coils
18
,
20
, one for each of the tip and ring wires, respectively. The coils are mounted to a mounting base
32
and are biased in the downward direction relative to or toward the mounting base by tip spring
22
and ring spring
24
. The heat coils
18
and
20
are maintained in an “up” or vertically offset position from the mounting base
32
by hardened solder lands or formations
30
.
A leaf spring
26
is partially contained within a sleeve
28
that is mounted to module
12
. The leaf spring is horizontally off-set or displaced from the tip and ring heat coils
18
,
20
and is in physical and electrical contact with a module or diode clip
29
for providing a grounding path from the module
12
through the base
32
for voltage surges. Particularly, the leaf spring
26
contacts the diode clip
29
at a node
46
contained within a conducting region
38
(depicted in dashed lines in FIG.
2
and shown in detail in
FIG. 3
) and is supported, in part, by a grounding device housing
36
.
In operation, and in the event of a current surge of relatively long duration through, for example, the tip wire
14
, the solder land
30
on tip heat coil
18
will melt, allowing heat coil
18
to be displaced downward under the urgency of spring
22
into abutment with base
32
and thereby connect to a common ground through base
32
. Since the module
12
is connected to both the tip and ring heating coils
18
,
20
, the assembly will tilt slightly in a direction of the movement of the heat coil.
In the event of a voltage surge such as from a lightning strike, the arc resulting therefrom will extend from the diode clip
29
to the leaf spring
26
through node
46
and be discharged to common ground through base
32
. A problem that occurs, however, is that the arc will generate a force that pushes against the leaf spring
26
, in the direction shown by arrow
34
, thereby deflecting and permanently bending the leaf spring
26
away from diode clip
29
, i.e. out of physical and possible electrical contact with module
12
. This result renders the prior art grounding mechanism unable to defend against any subsequently occurring voltage and/or current surges, leaving the delicate telecommunications equipment connected through module
12
particularly susceptible to damage from such subsequently occurring surges.
SUMMARY OF THE INVENTION
The present invention provides an improved grounding device for protecting telecommunications equipment from damaging voltage spikes that occur, for example, as a result of lightning strikes. The grounding device includes a mounting base to which the tip and ring wires of a communications line are connected. The mounting base provides a grounding path for allowing the discharge to ground of voltage spikes without causing damage to telecommunications equipment connected to the tip and ring wires. A pair of heat coils, one for each of the tip and ring wires, are provided. The heat coils are positionally biased in the direction of the mounting base by coil springs that operatively displace the heat coils to a grounding position against the mounting base in the event that a current surge of a relatively long duration is detected. An electronic module current carrying member is provided having a first leg for defining a first current path for carrying relatively short duration current generated from a large surge in a first direction along the grounding path. The current carrying member also includes a second leg which defines a second current path for carrying the short duration current in a second direction. A voltage discharge member for discharging the relatively short duration current through the grounding path is positioned in contact with the current carrying member between the first and second legs at a location closer to the second leg so that the second current path is shorter than the first current path. The positioning of the voltage discharge member in this manner reduces the opposing electromagnetic force applied from the current carrying member against the voltage discharge member and prevents the voltage discharge member from becoming deformed and, thereby, spaced or detached from the current carrying member by a high surge.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.
REFERENCES:
patent: 4733325 (1988-03-01), Loesch
patent: 4796150 (1989-01-01), Dickey et al.
patent: 4876621 (1989-10-01), Rust et al.
patent: 4958254 (1990-09-01), Kidd et al.
patent: 5587861 (1996-12-01), Wieloch et al.
Daoud Bassel Hage
Pelosi Walter
Sumetskiy Mikhail
Avaya Technology Corp.
Huynh Kim
Sherry Michael J.
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