Electricity: circuit makers and breakers – Switch activation inhibitor – Actuator locking device
Reexamination Certificate
2001-04-30
2002-04-02
Friedhofer, Michael (Department: 2832)
Electricity: circuit makers and breakers
Switch activation inhibitor
Actuator locking device
C200S043160, C200S050020
Reexamination Certificate
active
06365851
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of manually actuable switch handle guards.
BACKGROUND OF THE INVENTION
A number of designs are available to prevent accidental or inadvertent manipulation of a switch, and to discourage tampering therewith. Typically, these designs include a cover or pseudocover over the normal switch cover. Other systems provide a recessed handle or require a tool for use.
Likewise, it is known to provide modular or removable mechanical switches in electrical apparatus. An extraction tool may be used to remove the mechanical switch from its electrical socket or mounting.
SUMMARY OF THE INVENTION
The present invention provides a switch guard, advantageously combined with a switch extraction tool, such that the switch must be deactivated prior to removal from a circuit. The extraction tool thus is either inhibited by switch activation, or automatically deactivates the switch prior to releasing the switch.
The switch guard, for example, comprises removable covering portion, normally disposed to prevent manual actuation of the switch, in at least one operating position thereof. The cover, when removed, either automatically switches the position of the switch, or provides manual access to the switch handle. The switch guard advantageously also serves as an extraction tool for applying an extractive force on the switch, which would permit removal of a socketed switch. Preferably, the switch guard as extraction tool either automatically switches the switch into a desired position, or is impaired in providing the required extraction force if the switch is not in the desired position. Thus, the switch guard provides a safety feature.
According to a preferred embodiment, the switch guard, comprises a set of fulcrum pins rigidly mounted to the switch, about which a combination covering portion and extraction tool rotates. According to this embodiment, as the combination covering portion and extraction tool is rotated about the fulcrum pins, and displaced relatively apart from the body of the mechanical switch, a member of the combination covering portion and extraction tool exerts a force on the switch toggle, causing the switch to turn the OFF position, if it is not already in that state. When the combination covering portion and extraction tool is in the fully displaced apart from the body, it is particularly adapted as a manual handle to apply an extractive force on the fulcrum pins, and thereby apply the extractive force from the switch body away from an underlying socket.
Thus, the switch guard serves a first protective function to prevent accidental change in position of the switch, and further to prevent ready extraction of the switch.
Preferably, the fulcrum pins are disposed on a pair of walls which laterally protect the switch lever handle, which may be part of a manufactured switch, retrofit to a standard switch type, or provided as modular kit arrangement.
The combination covering portion and extraction tool may be provided with an aperture, allowing ready access to the toggle of the switch by a finger, for movement to the operating position, and/or to provide visual access to the switch toggle, for example to display a trip status.
When integral with the switch as manufactured, the switch toggle (lever handle) may be designed to efficiently interact with the extraction tool, and thus may have a cam surface or the like to facilitate smooth operation. On the other hand, when part of a modular kit or retrofit installation, the extraction tool operates against the normal manually operable toggle.
According to a preferred embodiment, the extraction tool comprises a manually graspable handle member and a pair of lateral recesses, cooperating with a pair of fulcrum pins to provide a pivoting structure. The handle is displaced from the lateral recess by an elongated member, which is, for example, a pair of arms. The normal position of the extraction tool is such that the extraction tool covers the switch lever. The extraction tool may have an open aperture, for example, a space between the pair of arms, which allow visual access to the switch toggle, for example. in order to permit visual examination of its position. In addition, the toggle may be displaced manually, if it is in an accessible position, by presenting a finger through the open aperture.
The extraction tool also comprises an actuation member, linked to the toggle at a position opposite from the manually graspable member with respect to the lateral recesses (i.e., the axis of rotation), such that when the extractor handle is withdrawn away from the mechanical switch body, the actuation member applies a force against the switch toggle. Preferably, the actuation member is rigidly linked to the extraction handle, such that movement of the extraction handle produces a corresponding movement in the actuation member, to displace the switch toggle, causing an alteration of the switch status, for example from “On” to “OFF”. The actuation member preferably has a flat cam surface for pressing against the switch toggle. Further, this cam surface is preferably hollow, such that when the extraction handle is in its normal position, the switch toggle sits hidden beneath it.
The extraction handle may, for example, freely pivot between the normal and extended position, have a spring return, or a set of detents for retaining a desired position. Preferably, the extraction handle freely pivots, and is generally held in the normal position by the toggle, which is typically itself spring loaded. Thus, when in the normal position, with the switch activated, the actuation member rests against the switch toggle and is retained in the retracted position. After the switch is tripped or OFF, the extraction handle freely rotates to the extended position. To reactivate the switch, the toggle lever is returned to the normal (retracted) position, and a finger or tool inserted into the aperture between the arms of the extraction tool, to urge the toggle into the activated or ON position, thus retaining the extraction tool in the normal position, since the toggle then rests against the inner surface of the hollow portion.
In order to remove the mechanical switch, which is set in a socket providing electrical connections, a tensile force is applied to the extraction tool handle. This force initially deactivates the switch (or ensures that the switch is deactivated), by applying a force to the toggle, urging it into the OFF or deactivated position, or ensuring it is already in this position, and then, when the extraction tool handle is fully extended, transmits a tensile force to the fulcrum pins, switch guard, switch, and ultimately to the electrical socket. The electrical socket is held together by a combination of friction and elastic forces, and when these are overcome, the switch is removed from the socket.
The handle guard is, for example, integral with, or held to the switch body by screws or other type of fasteners or fastening means. Typical known switches are with fasteners for attaching a faceplate or the like, and thus in the case of a retrofit design, the fasteners may be standardized. Such fasteners may include screws, bolts, rivets, or the like. Alternately, the handle guard may be fastened to the switch by glue or other adhesive, or welded in place.
It is therefore an object of the invention to provide a switch extraction system which ensures that the switch is deactivated prior to permitting extraction of the switch.
It is a further object of the invention to provide a retrofit kit for a manually operable switch that provides an extraction tool for removing the switch from a socket, while ensuring that the switch is deactivated prior to removal.
It is a still further object of the invention to provide a switch guard having an extensible handle for unidirectionally altering a toggle or switch handle lever position, providing access for a second switch activation means for unidirectionally altering the switch handle lever in the opposite direction. This second switch activation means may b
Airpax Corporation L.L.C.
Friedhofer Michael
Milde & Hoffberg LLP
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