Electricity: electrothermally or thermally actuated switches – Electrothermally actuated switches – Space discharge device
Reexamination Certificate
1999-09-13
2001-03-20
Picard, Leo P. (Department: 2835)
Electricity: electrothermally or thermally actuated switches
Electrothermally actuated switches
Space discharge device
C337S017000, C337S401000, C337S405000, C361S119000, C361S124000
Reexamination Certificate
active
06204746
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to a protection device for use in the telecommunications field for protecting equipment connected to tip and ring conductor pairs. More particularly, the present invention relates to a thermal overload mechanism for providing a grounding path for tip and ring conductors during a power cross occurrence.
2. Description of the Related Art
Telecommunications systems typically employ protection mechanisms such as grounding devices located proximate a service subscriber location or central office to protect telecommunications lines from detrimental power surges and voltage spikes. The voltage spikes are usually caused by lightning striking telephone lines, and the power surges are caused by power crosses between telephone lines and high voltage power cables which occur, for example, as a result of high winds. In particular, grounding devices are used to provide a path to common ground for voltage surges caused by lightning strikes to prevent such surges from damaging equipment connected to tip and ring wires as well as to prevent injury to personnel working on the wires or on equipment.
In the event of a power cross situation, however, which results in the application of high currents and resulting high temperatures to protection mechanisms, a grounding path must also be formed to provide for the discharge of power surges which would, otherwise, adversely affect delicate telecommunications equipment and injure personnel. Known grounding protection mechanisms of the type employing solid state devices typically include a combination of a fuseable pellet or link in conjunction with a biasing spring. The fusable pellet will melt from the heat generated during a power cross occurrence, in which event the biasing spring will maintain connection of the tip/ring pair through a common ground. The drawback of this technique, however, is that the additional elements (such as the spring and fuseable link) must be added to the protection mechanisms during assembly, thereby increasing the cost and assembly time for such devices.
SUMMARY OF THE INVENTION
The present invention is directed to a thermal overload mechanism for use in protecting telecommunications equipment from damage resulting from power cross occurrences. The inventive mechanism includes a clip element connectable to a grounding path and having front and rear spring members. A spacer having a recess formed therein holds a solid state device which is electrically connected to the tip and ring conductors. The recess has a meltable or breachable back wall membrane. When the solid state device is placed within the recess and the spacer is placed within the clip element, the front spring member presses against the solid state device and the rear spring member presses against the membrane to provide a clamping force between the solid state device and the membrane. In the event of a power cross occurrence wherein current resulting in increased heat is applied to the solid state device, the heat will melt or break the back wall membrane of the spacer, causing direct electrical contact between the second spring member and the tip and ring conductors. In this manner, a grounding path is provided from the tip and ring conductors through the clip element and to common ground without traversing a conducting path through the solid state device. This serves to protect equipment connected to the tip and ring conductors as well as personnel in contact with such equipment and conductors from damaging current generated by the solid state device during a power cross situation.
In a preferred embodiment, a lead contact is included for interfacing the tip and ring conductors with the solid state device and membrane.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawing. 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. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures described herein.
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Kane Adam Stuart
Pelosi Walter
Avaya Inc.
Picard Leo P.
Vortman Anatoly
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