Abstract: A tennis racket including a shaft that has a handle and a head attached thereto having a diamond-shaped frame. A length dimension of the frame is longer than a width thereof and is parallel to the shaft. A string groove is continuously disposed around the frame. A plurality of string holes is disposed within the string groove. A single length of string is continuously disposed through the string holes to string the tennis racket. A pair of tie off members is centrally disposed within the string groove on one side of the frame proximal a first corner of the frame. A central portion of the string centrally disposed within the frame forms a sweet spot which is larger than the sweet spots of other tennis rackets due to the diamond shape of the frame thereby propelling the tennis ball with more power and a more accurate aim.

Abstract: A circuit breaker interlocking mechanism characterized by a pair of circuit breakers connected to different power supply sources in comprising a locking member pivotally mounted between the circuit breakers for preventing one circuit breaker from being actuated when the other is in a preselected operating position.

Abstract: A circuit breaker having an improved compact thrust transmitting spring for opening the contacts in a minimum of time.

Abstract: A shield for avoiding the accumulation of contaminants and dust on stabs of loadcenter bus bars during handling and shipping characterized by a molded sheet-like member having spaced blisters extending from one side of the member, and the blisters being comprised of a semi-rigid material adapted to cover the bus bar and stabs detachably clampingly engaged in place.

Abstract: Ground fault circuit breaker structure characterized by an insulating integral housing having a pair of side-by-side compartments that are separated by a partition wall. A circuit breaker is located in one compartment and a ground fault detector is located in the other compartment and isolated from the circuit breaker. The ground fault detector comprises a differential transformer comprising a current monitoring core, a plurality of primary windings on the core, each being one of a line and a neutral conductor of an A.C. electrical distribution system, a secondary winding sensing current unbalance between the primary windings, means responsive to a predetermined sensing signal to open the line conductor; and the line conductor extending between the circuit breaker trip means and through aperture means in the partition wall and through the magnetic core and back through the aperture means to the load terminal.

Abstract: Ground fault circuit breaker structure characterized by an insulating integral housing having side-by-side compartments that are separated by partition walls. A circuit breaker is located in each of two compartments and a ground fault detector is located in a compartment between the circuit breakers and isolated from the circuit breakers by the partition walls.

Abstract: Ground fault interrupter apparatus of the differential transformer type is provided with an additional output transformer, the primary of which is connected between a line conductor and the neutral conductor of an A.C. system with a current limiting resistor adjacent the primary winding. The secondary of the output transformer is the neutral conductor. THe saturation properties of the core of the output transformer are such that during each half cycle a voltage pulse is induced in the secondary. The voltage pulse is of no consequence in the system during normal conditions but if a grounded neutral condition exists a current is produced in the neutral conductor unbalancing the differential transformer and interrupting operation.

Abstract: A rain-tight outdoor enclosure for containing electrical apparatus characterized by a box-like container and a detachable cover hingedly mounted. The container comprising an open vertical side and a open bottom end. The cover comprising a wall coextensive with the open side and having opposite flanges overlapping portions of corresponding sidewalls of the container. Means for hingedly mounting the cover on the container for movement between open and closed positions and including a groove in each opposite container side wall and a protrusion in each opposite flange of the cover which protrusions extend into the grooves and are slidable therein between open and closed positions of the cover. Latching means for holding the cover in the open position and comprising a projection on at least one of the side walls and abuttable with the cover when the cover is opened and each protrusion is in the open position in its groove.