Abstract:
A lockout for circuit breakers provides a channel holding the circuit breaker toggle bar with a set screw that may be accessed only when an eye of the lockout is free of a padlock shackle. The eye is oriented vertically so that the padlock may be rotated to not interfere with adjacent circuit breakers being locked out or operated.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     BACKGROUND OF THE INVENTION 
     The present invention relates to electrical circuit breakers including motor controllers and, in particular, to a lockout preventing unauthorized activation of a circuit breaker or motor controller. 
     Safety practice requires that electrically powered machines be isolated from power before adjustment, maintenance, or repair of the machine by a human operator. Such isolation must be done in a manner to prevent accidental reconnection. 
     This isolation may be accomplished by opening the circuit breaker associated with the machine and locking the circuit breaker toggle in the “off” position using a “sealed” wire connection or a padlock and a special locking fixture. As used herein, the term “circuit breaker” should be considered to include manual motor controllers and the like. 
     Referring to FIG. 1, a prior art single-pole, miniature-style circuit breaker  10 , includes a front escutcheon plate  12  having an outer edge  14  and an opening  16  therein through which a toggle operator  18  extends. The toggle operator  18  pivots in a longitudinal direction  20  between a downward OFF position  22  (as shown in FIG.  1 ), and an upward ON position  24 . A free end of the toggle operator  18  is attached to a transversely extending bar toggle  26  that may be easily operated by a person&#39;s finger. 
     Referring also to FIG. 2, a prior art lockout  30  for such a circuit breaker  10  uses an aluminum extrusion having a transversely extending channel  32  with opposed lower wall  34  and upper wall  36 . The channel  32  is sized to receive the toggle bar  26  when it is in the OFF position. A set screw  38  passes through the upper wall  36  into the channel  32  so that the toggle bar  26  may be captured between a tooth  40  projecting inward from lower wall  34  and a pointed tip of the set screw  38 . 
     The upper wall  36  attaches to a foot  42  which abuts the escutcheon plate  12  at a front upper edge  14  of escutcheon plate  12 . In this way, motion of the toggle bar  26  in an upward arc along the longitudinal axis  20 , such as would tip the lockout  30 , is resisted by pressure of the foot  42  against the front surface of the escutcheon plate  12 . As shown in the drawing, for some circuit breakers  10 , the foot  42  of the lockout  30  is very close to the edge  14  of the escutcheon plate  12  and may slip over that edge  14  allowing activation of the circuit breaker  10  despite the lockout  30 . 
     The head  46  of the set screw  38  extends into an opening of an eye  44  attached generally to the upper wall  36  and providing a cylindrical transverse aperture. An access hole  48  in the wall of the eye  44 , opposite the head  46  of the set screw  38 , allows insertion of a screwdriver blade  50  to engage the head  46  for tightening the set screw  38  against the toggle bar  26  or loosening it therefrom. 
     Referring also to FIG. 3, a shackle  52  of a padlock may be inserted through the eye  44  to block access by the screwdriver blade  50  to the head  46  of the set screw  38 . Generally, the shackle  52  must be somewhat smaller than the diameter of the eye  44  because of the protrusion of the head  46  into the aperture of the eye  44 . The transverse extending eye  44  requires that the shackle  52  be positioned so that the case  54  of the padlock lies across adjacent circuit breakers  10 ′ and  10 ″ interfering with operation of these circuit breakers  10 ′ and  10 ″ and preventing the use of a second lockout on these adjacent circuit breakers  10 ′ and  10 ″. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a mechanical lockout also engaging a toggle bar of a circuit breaker but in which the eye is positioned to allow a padlock used with the lockout to hang edgewise. This change in the orientation of the padlock reduces or eliminates interference between the padlock and adjacent circuit breakers and/or lockouts on those circuit breakers. An improved foot on the lockout includes a heel engaging an aperture of the escutcheon plate of the circuit breaker preventing slippage of the lockout with movement of the toggle bar of the circuit breaker. The set screw of the lockout is further mounted in a counter bore below the surface of the eye allowing proportionally larger shackled locks and improved tamper resistance. 
     More specifically, the present invention provides a lockout for a circuit breaker having a toggle operator switchable between an ON and OFF position. The lockout includes a transverse channel having opposed first and second walls for receiving the toggle operator therebetween, the first wall including a hole extending therethrough. A screw fitting within the hole can be extended toward the second wall by rotation of the screw to clamp the toggle operator within the channel. A foot attached to the channel engages a portion of the circuit breaker, other than the toggle operator, to resist switching of the toggle operator when the toggle operator is clamped in the channel. A longitudinal eye is attached to the first wall to receive a padlock shackle along a direction substantially perpendicular to the channel so that the shackle blocks access to the head of the screw. 
     Thus, it is one object of the invention to provide an improved orientation of the eye of a lockout allowing adjacent circuit breakers to be operated or to be locked out without interference from the padlock. 
     The screw may be a set screw having its head positioned within a counter bore of the hole so that the received shackle covers the counter bore. 
     Thus it is another object of the invention to eliminate access to the head of the set screw and to allow the use of a larger diameter shackle associated with commonly available padlocks and/or to reduce the necessary size of the eye. 
     The hole may open into the longitudinal eye. 
     Thus, it is another object of the invention to prevent movement of the shackle within the eye from allowing access to the set screw. 
     The toggle of the circuit breaker may extend from an opening in an escutcheon plate and the foot may include a heel portion fitting within the opening. 
     Thus, it is another object of the invention to provide a more positive lockout that cannot be defeated by a sliding of the lockout mechanism along the surface of the escutcheon plate. 
     The foot may also include a toe fitting over the outer edge of the escutcheon plate. 
     Thus it is another object of the invention to provide a positive indication of a proper fitting of the lockout to the circuit breaker that may indicate that the lockout is not being used on the toggle when the toggle is in the OFF position as is desired. 
     The eye may be oriented so that the shackle of the padlock is substantially vertical when the circuit breaker is mounted so that the toggle operator is switched in a vertical direction. 
     Thus, it is another object of the invention to allow the padlocks to hang stably without gravitationally induced twisting and interference. 
     The channel may fully cover the toggle operator when the toggle operator is positioned within the channel. 
     Thus, it is another object of the invention to better enclose the toggle to reduce tampering and removal of the operator by twisting. 
     Alternatively, the channel may extend at least two times the length of the toggle operator to engage toggle operators of adjacent circuit breakers. 
     It is thus another object of the invention to provide the ability to lockout multiple adjacent circuit breakers. 
     These particular features, objects and advantages may apply to only some embodiments falling within the claims and thus do not define the scope of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a standard miniature circuit breaker and a prior art lockout before assembly on the circuit breaker as has been described above in the background of the invention; 
     FIG. 2 is a side elevational view of the prior art lockout when assembled to the miniature circuit breaker of FIG. 1; 
     FIG. 3 is a front elevational view of the lockout assembled to a circuit breaker in a bank of circuit breakers showing placement of the shackle of a padlock through the eye of the lockout where the padlock blocks the adjacent circuit breakers; 
     FIG. 4 is a figure similar to that of FIG. 1 showing a lockout of the present invention having a longitudinal eye; 
     FIG. 5 is a side elevational view of FIG. 4 showing placement of a set screw for engaging the toggle of the circuit breaker and an access path for a screw driver to that set screw; 
     FIG. 6 is a figure similar to that of FIG. 3 showing orientation of a padlock using the present invention such as minimizes interference with adjacent circuit breakers; 
     FIG. 7 is a side elevational cross section of an alternative embodiment of the invention assembled to a circuit breaker showing a heel portion of the lockout that engages an access hole in the escutcheon plate of the circuit breaker; and 
     FIG. 8 is an alternative embodiment of the lockout of FIG. 4 in perspective such as provides simultaneous lockout of multiple, adjacent circuit breakers. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 4 and 5, a lockout  60  of the present invention provides a transversely extending channel  62  having an opposed first wall  66  and second wall  64  such as may receive the toggle bar  26  along its entire length. A set screw  68  passes through the first wall  66  and into the channel  62  where it may compress the toggle bar  26  between the end of the set screw  68  and the inner surface of the second wall  64  capturing the toggle bar  26  within the channel  62 . 
     The channel  62  is sized to minimize the gap between the channel  62  and the toggle bar  26 , when the toggle bar  26  is in the channel  62 , preventing tampering with the set screw  68 . The length of the channel  62  may be substantially equal to the transverse length of the toggle bar  26  so that the channel  62  stabilizes and supports the toggle bar  26  along its entire length. 
     Extending from the first wall  66  is a foot  70  sized to rest in part on the front surface of the escutcheon plate  12  of the circuit breaker  10  above the toggle bar  26 . The foot includes a heel  73  fitting within an opening  16  in the escutcheon plate  12  through which the toggle operator  18  extends. The heel  73  prevents upward motion of the lockout  60  along axis  20  when the lockout  60  is engaged with the toggle bar  26 . 
     The foot may also include a toe  72  fitting over the edge  14  of the escutcheon plate  12  to help locate the lockout  60  and to prevent its use in inverted fashion to hold the toggle in the ON position. The proper use of the lockout  60  is further emphasized by lettering  80  molded on the side of the lockout  60  between the foot  70  and the first wall  66  which reads: “LOCK OFF ONLY”. 
     An eye  82  is attached to the body of the lockout  60  and positioned over a counter bore  84  leading to the head  86  of the set screw  68 . The length of the set screw  68  and the size of the counter bore  84  is adjusted so that when the set screw  68  is rotated to clamp the toggle bar  26 , the head  86  of the set screw  68  is nested within the counter bore  84  and does not to interfere with a shackle of a padlock passing through the eye  82 . Nevertheless, when a shackle is placed within the eye  82 , the portion of the shackle within the eye  82  covers the counter bore  84  and access to the head  86  of the set screw  68  is prevented. 
     When the eye  82  is free of the shackle, a screwdriver blade  50  may be inserted angularly through the longitudinally extending aperture of the eye  82  to fit within the counter bore  84  for turning the set screw  68  into engagement or release from the toggle bar  26 . A wall of the eye  82  opposite the counter bore  84  may be notched to improve access by the screwdriver blade  50 . 
     Referring now to FIG. 6, the shackle  52  of a padlock may extend vertically through the eye  82  so that the case  54  of the padlock may be turned so as not to interfere with adjacent circuit breakers  10 ′ or  10 ″. In this manner, lockouts may be simultaneously used for each of the adjacent circuit breakers  10 ′ through  10 ″ and the padlock does not interfere with the operation of the adjacent circuit breakers  10 ′ through  10 ″. The eye  82  may be positioned on the lockout  60  so that when it is installed on the circuit breaker  10 , the shackle  52  of the padlock is substantially vertical and thus does not have a tendency to twist. 
     Referring now to FIG. 7, the shape of the channel  62  and of the foot  70  and heel  73  of lockout  60 ′ may be modified to conform to circuit breakers  10  of different styles following the above described general principles. In this example, the heel  73  is increased in size and the toe eliminated. The height of the eye  82 ′ is lowered while still allowing the shank of the padlock passing through the eye  82 ′ to cover the counter bore  84  in which the set screw  68  is placed. 
     Referring to FIGS. 6 and 8, the lockout of FIG. 4 may be modified to produce a lockout  60 ″ having a transversely wider channel  62  extending a multiple (2 or more) times the width of the toggle bar  26  so that the first and second walls  66  and  64  may cover and therefore lock more than one toggle bar  26  on adjacent circuit breakers  10  through  10 ″. 
     It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.