Electrical transmission or interconnection systems – Switching systems – Plural switches
Reexamination Certificate
1999-01-13
2001-02-06
Jackson, Stephen W. (Department: 2836)
Electrical transmission or interconnection systems
Switching systems
Plural switches
C307S115000, C307S125000
Reexamination Certificate
active
06184595
ABSTRACT:
FIELD OF THE INVENTION
This invention is generally related to an interlock for circuit breaker switches and, more particularly, pertains to a circuit breaker linkage assembly interlocking two opposing circuit breaker handles and preventing both circuit breakers from being ON at the same time.
BACKGROUND OF THE INVENTION
In today's electrical supply systems, there are occasions when alternate sources of electrical power are necessary or desirable. For example, the capability of switching from utility power to emergency generator power is very important for many businesses, hospitals and industries, and is also being employed in residential applications.
In certain applications, it is desirable for separate electrical circuits or even separate groups of electrical circuits to be arranged so that when one group of circuits is switched to a conductive state, another group of circuits is switched to a non-conductive state in alternating fashion. In some arrangements, it may be desirable to alternately switch a common load between separate power sources so that, as one power source is disconnected from the load, the second power source is connected to prevent interruption of power to the load. In order that the alternate switching may be effective essentially simultaneously, a need has been recognized to employ a coupling mechanism which functions to switch one circuit OFF as the other circuit is switched ON. Prior art interlocking systems provide an interlock for first and second aligned circuit breakers having first and second external operating handles oriented thereon such that the operating handles are parallel and disposed away from each other when the switches are OFF, and towards each other when the switches are ON. The interlock includes a linkage arrangement disposed across the face of the circuit breaker switches for applying a linear force between the first operating handle and the second operating handle. The linkage arrangement is formed such that pushing the first operating handle from an OFF position to an ON position pushes the second operating handle from an ON position to an OFF position. An example of an interlock of this type is disclosed in Flegel U.S. Pat. No. 5,648,646 issued Jul. 15, 1997.
The above-described interlock functions satisfactorily for switches which have parallel handles and which move along a common axis between their ON and OFF positions. However, it is common to feed utility or primary power to a load center through a main circuit breaker which is oriented perpendicularly to the branch circuit breakers. With this arrangement, the switch handle of the main circuit breaker moves between its ON and OFF positions in a direction perpendicular to the direction of movement of the branch circuit breaker switch handles. This construction prevents use of known prior art interlocks with the main circuit breaker, since known interlocks can only be used with aligned switch handles which move along a common axis.
It is thus desirable to provide an interlock mechanism which prevents two circuit breakers in nonparallel relation to each other, and possibly of different sizes, from being turned ON simultaneously. It is also desirable that the interlock mechanism permits both of the circuit breakers to be switched OFF at the same time.
Accordingly, it is an object of the present invention to provide a circuit breaker interlock which is useable when the circuit breakers have switches operational in transverse directions. A further object of the invention is to provide an interlock that prevents two power sources from supplying power to an electrical panel simultaneously. Yet another object of the invention is to provide an interlock that allows the circuit breakers to reside simultaneously in an OFF position so that no power is supplied to the electrical panel. Yet another object of the invention is to provide an interlock that is easily adaptable to commonly available circuit breakers and electrical panels. Yet another object of the invention is to provide an interlock which is relatively simple in its components and construction, and adaptable to other switching applications.
SUMMARY OF THE INVENTION
The present invention advantageously provides an interlock for circuit breakers installed in a standard electrical load center panel for the purpose of providing a safe and simple arrangement for providing power to the selected circuits from an alternate power source, such as a portable generator, during a utility power outage. The present invention enables the use of standard, off-the-shelf circuit breakers that, due to differences in size, construction and orientation when installed, cannot be arranged so that their handles more in the same direction.
In one aspect of the invention, an electrical panel has a first switch mechanism that is movable in a first direction, and a second switch mechanism movable in a second direction, non-parallel to the first direction. Both switches are operable between an ON and an OFF position, and are preferably associated with circuit breaker mechanisms which control the supply of electrical power to the electrical panel from a first or second power source, respectively. An interlock mechanism is interconnected between the first switch mechanism and the second switch mechanism to prevent movement of the second switch mechanism to an ON position when the first switch mechanism is in its ON position. The interlock mechanism also prevents movement of the first switch mechanism to its ON position when the second switch mechanism is in its ON position. In a preferred embodiment, the first and second switch mechanisms include first and second manually operable switch handles, and the interlock mechanism is interconnected between the first and second switch handles. In a preferred form, each switch mechanism is adapted for removable mounting to the electrical panel. The interlock mechanism includes a support structure adapted for engagement with the first and second switch mechanisms. A first interlock member is movably mounted on the support structure, and is engaged with the first switch handle for movement therewith in the first direction. A second interlock member is also movably mounted to the support structure, and is engaged with the second switch handle for movement therewith in the second direction. The first and second interlock members include interference structure to prevent movement of the second switch member to an ON position when the first switch member is in its ON position, and for preventing the movement of the first switch member to an ON position when the second switch member is in its ON position.
The interference structure of the first and second interlock members preferably includes structure defining a notch. The notch is formed in one of the interlock members, hereafter referred to as the notched interlock member, and extends in a direction transverse to the direction of movement of the notched interlock member. The other interlock member is preferably in the form of an engagement interlock member having corresponding interference structure adapted to be selectively received within the notch. When the first switch member, to which the notched interlock member is mounted, is moved to its OFF position, the notch is aligned with the interference structure of the engagement interlock member. This enables movement of the second switch member, to which the engagement interlock member is mounted, to its ON position. Preferably, the notched interlock member defines an interference surface adjacent the notch which is in alignment with the interference structure of the engagement interlock member. Movement of the second switch member to its ON position is prevented by the interference structure when the first switch member, to which the notched interlock member is mounted, is in its ON position.
The support structure preferably includes a support plate configured to engage a shoulder defmed by each of the first and second switch mechanisms adjacent to the first and second switch members, respectively. A post membe
Andrus Sceales Starke & Sawall LLP
Jackson Stephen W.
Polk Sharon
Reliance Controls Corporation
LandOfFree
Interlock for transversely oriented circuit breaker switches does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Interlock for transversely oriented circuit breaker switches, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Interlock for transversely oriented circuit breaker switches will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2563814