Electricity: electrical systems and devices – Safety and protection of systems and devices – High voltage dissipation
Reexamination Certificate
2000-01-14
2001-12-04
Ballato, Josie (Department: 2836)
Electricity: electrical systems and devices
Safety and protection of systems and devices
High voltage dissipation
C361S117000, C361S120000, C361S124000
Reexamination Certificate
active
06327129
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention is directed to an electrical surge protection device of the type used to protect equipment and electrical circuits from being damaged by overvoltage surges and/or excessive surge currents.
Surge protection devices may be used to protect power lines, communication lines and electrical equipment connected to the power lines and communication lines from overvoltage surges, such as those caused by lightning or power cross conditions, for example. A power cross condition, which may occur as a result of a downed power line, consists of a high voltage and a high current at an alternating frequency, such as 60 Hz.
During an overvoltage surge, a surge protection device may provide temporary surge protection by shunting the overvoltage surge to ground. In the presence of a prolonged overvoltage condition, a surge protection device may also be designed to fail in a short-circuit state. Various embodiments of surge protectors are disclosed in U.S. Pat. No. 5,388,023 to Boy, et al., U.S. Pat. No. 5,500,782 to Oertel, et al., and U.S. Pat. No. 5,880,919 to Napiorkowski, et al.
SUMMARY OF THE INVENTION
The invention is directed to a surge protector assembly having three terminals, a gas discharge tube having a first conductive end and a second conductive end opposite the first conductive end, a first metal oxide varistor conductively connected to the first end of the gas discharge tube, and a first bracket arm associated with the first end of the gas discharge tube. The first bracket arm is movable between a steady-state position in which the first bracket arm causes the first terminal to be conductively separated from the third terminal and a shorting position in which the first bracket arm causes the first terminal to be conductively connected to the third terminal. The first bracket arm is spaced from the first end of the gas discharge tube by a first distance when the first bracket arm is in its steady-state position and by a second distance when the first bracket arm is in its shorting position, with the first distance being greater than the second distance, and the first bracket arm is spring-biased towards its shorting position.
The surge protector assembly includes a first holding member associated with the first bracket arm and a first portion of eutectic material, such as solder, that bonds the first bracket arm to the first holding member when the first bracket arm is in its steady-state position so that the first holding member holds the first bracket arm in its steady state position. The first bracket arm is released by the first holding member upon a change of state, such as melting, of the first portion of eutectic material so that the first bracket arm moves to its shorting position.
The surge protector assembly also includes a second metal oxide varistor conductively connected to the second end of the gas discharge tube and a second bracket arm associated with the second end of the gas discharge tube. The second bracket arm is movable between a steady-state position in which the second bracket arm causes the second terminal to be conductively separated from the third terminal and a shorting position in which the second bracket arm causes the second terminal to be conductively connected to the third terminal. The second bracket arm is spaced from the second end of the gas discharge tube by a third distance when the second bracket arm is in its steady-state position and by a fourth distance when the second bracket arm is in its shorting position, with the third distance being greater than the fourth distance, and the second bracket arm is spring-biased towards its shorting position.
The surge protector assembly further includes a second holding member associated with the second bracket arm and a second portion of eutectic material that bonds the second bracket arm to the second holding member when the second bracket arm is in its steady-state position so that the second holding member holds the second bracket arm in its steady state position, the second bracket arm being released by the second holding member upon a change of state of the second portion of eutectic material so that the second bracket arm moves to its shorting position.
Each of the bracket arms may have a hole formed therein, and a portion of each of the holding members may pass through one of the holes formed in the bracket arms. Each of the holding members may be provided with a relatively large-diameter portion and a relatively small-diameter portion, with the relatively small-diameter portion of each holding member passing through one of the holes in the bracket arms. The relatively large-diameter portion of each holding member may be bonded to one of the bracket arms by the eutectic material.
Each end of the gas discharge tube may have a hole formed therein, and each metal oxide varistors may be disposed in one of the holes formed in the ends of the gas discharge tube. The surge protector assembly may also include a pair of conductive mounting members that support the ends of the gas discharge tube, with each conductive mounting member having a first end connected to the first end of the gas discharge tube and a second end conductively connected to the first terminal, and the bracket arms may make physical contact with the conductive mounting members when the bracket arms are in their shorting positions. The surge protector assembly may also include a printed circuit board and a support structure that supports the gas discharge tube on the printed circuit board, and the surge protector assembly may be disposed within a housing and provided as a complete surge protector.
The features and advantages of the present invention will be apparent to those of ordinary skill in the art in view of the detailed description of the preferred embodiment, which is made with reference to the drawings, a brief description of which is provided below.
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Joslyn D
Martin David
Oertel H. Wolfgang
Ballato Josie
Bourns Inc.
Marshall Gerstein & Borun
Quinones Miguel A.
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