BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevation of an exemplary lock-off device according to one embodiment of the present invention from the side for facing the circuit breaker.
FIG. 2 illustrates front perspective views of both right side and left lock-off devices on either side of a circuit breaker but not attached thereto.
FIG. 3 illustrates the lock-off device in the operable position preventing a circuit breaker handle from being moved to an ON position and locked in place by a padlock.
FIG. 4 is a side perspective view similar to FIG. 2 illustrating both right side and left side lock-off devices on either side of and attached to a circuit breaker with the retention arms in the non-operable non-lock-off positions.
DETAILED DESCRIPTION OF THE CURRENT EMBODIMENT
Referencing the drawings, and especially FIG. 1, exemplary embodiments of the lock-off device 11 of the present invention are shown. The lock-off device 11 comprises a body 13, having means, collectively 15, for mounting the body 13 to a circuit breaker 14. The body has a ring 17 or other substantially annular structure forming a throughhole or aperture 19 being sized for accepting a securing device such as the shackle 21 of a padlock 23 (FIG. 3). A lock-off arm 25 is pivotally attached to the body 13 by a securing nub 27 and has a complementary ring 28 with an annular void 30. A biasing washer 29 is fitted between the nub 27 and the lock-off arm 25 to bias the lock-off arm 25 towards the body 13. An arm retention nub 31 for frictionally retaining the complementary ring 28 is formed on the body 13. An alignment tab 33 also extends from the body 13.
The body 13 has a generally planar surface 35 for abutting a side wall 37 (FIG. 2) of the circuit breaker 14. The body 13 and its respective parts are desirably molded from a nonconductive thermoplastic or clear polycarbonate resin so as to not obstruct any side markings on the circuit breaker 14 or other accessory attached thereto. Other materials may be suitably used according to the parameters of the invention as would be understood by those of skill in the art. Desirably the body is not more than one quarter the thickness of its associated circuit breaker case, such that the mounting of every four circuit breakers with attached lock-off accessories would only take the space of five circuit breakers on a distribution rail. Beyond this, consideration must be given to the trade off between strength and flexibility of the body 13 in accomplishing the side mounting and lock-off functionality of the present invention. Likewise, the overall shape of the body 13, such as including the back side cutout 34 for termination clearance for connections to the circuit breaker 14, will be determined by the overall considerations of the circuit breaker 14 and lock-off device 11 functionality when placed in combination. The body 13 has first and second areas of reduced thickness 39, 41 respectively, at front and back ends 43, 45, respectively, of the body 13, for allowing flexure of the body 13 to seat the means 15 for mounting, which extend therefrom, onto the circuit breaker 14. The body ring 17 extends upwardly from the body 13 to place it substantially above the surface 47 of the circuit breaker 14 bearing its handle 49.
The exemplary means 15 for mounting the planar surface 35 of the body 13 to a side wall 37 of the circuit breaker 14, are arms 36 with tabs, or hooks, 38 desirably for engaging the corners or preformed recesses (not shown) in the case of the circuit breaker 14, and will generally result in a tenacious engagement and positioning of the body 13 with the circuit breaker 14. Alternatively, adhesives or other means for mounting may be suitably used according to the parameters of the invention as would be understood by those of skill in the art. In some embodiments the exemplary hooks are designed, i.e., the size, shape, and materials are selected, to be frangible so as the fracture if the lock-off device 11 is attempted to be removed above a predetermined force, thus evidencing improper interference with the function of the lock-off device 11.
The lock-off arm 25 is pivotally attached to the body 13 such as by heat staking the securing nub 27. The lock-off arm 25 carries an engagement tab 51 attached thereto which extends inwardly from the body 13 in a direction to be placed over the handle surface 47 of the circuit breaker 14 and in interference with the circuit breaker handle 49 when the lock-off arm 25 is in operable position as shown in FIG. 3 thus preventing movement of the circuit breaker handle 49 from the OFF position (shown) to the ON position. When the lock-off arm 25 is pivoted, in the exemplary embodiment roughly sixty degrees, into the non-operable, non-lock-off position, the engagement tab 51 rests on top of the circuit breaker 14 out of the way of the handle 49 as placed in the ON position. The complementary ring 28 of lock-off arm 25 is also desirably substantially hidden between the body 13 and the circuit breaker 14 and substantially beneath the handle-bearing surface 47 of the circuit breaker 14.
The engagement tab 51 is shown as a generally “L”-shaped arm with a long leg 53 extending inwardly and perpendicular from the body 13 and a short leg 55 extending perpendicularly from the long leg 53 toward the circuit breaker handle 49. However, the engagement tab 51 may otherwise be suitably sized and shaped according to the dictates of the breaker application. Considerations of engagement tab 51 size and shape, location of the pivot point, circuit breaker handle geometries to be accommodated, and any other associated circuit breaker accessory attachment layouts, may all affect the design of the engagement tab 51.
Referencing especially FIG. 3, the lock-off arm 25 in the operable position will have its complementary ring 28 adjacent to the body ring 17 for concurrently accepting the shackle 21. The engagement tab is thus placed in a position to prevent the circuit breaker handle from moving to an ON position and securable in said position by the shackle 21 or other securing device being placed concurrently through the complementary ring 28 and the body ring 17. In the exemplary embodiment it will be understood that the engagement arm 51 cannot be placed and locked in a position to maintain the circuit breaker 14 in an ON position. However, in alternative embodiments, the analogous pivot point of the lock-off arm, the geometry and placement of the voids for the body ring and the lock-off arm ring, and location and shape of the engagement arm, may be modified to allow such alternative embodiments to encompass both of a lock-off and a lock-on functionality is such is desired. The lock-off arm 25, including engagement arm 51, may be made of stainless steel or other suitable materials. The biasing washer 29, such as a Bellevue washer or the like, may be applied before the heat staking of the securing nub 27 and likewise made of stainless steel or other suitable materials.
Having thus described a side mounted lock-off device for a circuit breaker; it will be appreciated that many variations thereon will occur to the artisan upon an understanding of the present invention, which is therefore to be limited only by the appended claims.
Patent Application
20080073187
