Lockout device for high voltage circuit breaker

An improved lockout assembly is provided for a circuit breaker to lock the switch handle into a selected switch position. The lockout assembly includes two main elements, each having a respective foot for engaging a portion of the upper housing wall of the circuit breaker. The first foot is inserted into a groove in the upper housing wall, and the second foot is inserted into an adjacent aperture (e.g., a slot) in the upper housing wall. The first foot is slid under and into engagement with a first portion, and the second foot is slid under and into engagement with a second portion of the upper housing wall. At the same time the repsective two feet are placed in engagement with the respective portions of the upper housing wall, two holes, one on each of the respective two main elements of the assembly, are placed in registration; and a locking device, such as a special scissors equipped with a padlock, is installed through the registered holes to secure the lockout assembly on the circuit breaker. When the lockout assembly of the invention is secured on the circuit breaker, the switch handle of the circuit breaker is locked into the selected switch position and prevented from being switched to another switch position.

TECHNICAL FIELD OF THE INVENTION 
The present invention relates to an apparatus for safely and conveniently 
locking an individual circuit breaker (e.g. a high voltage, 480 volt AC, 
circuit breaker) in a distribution panel in the off (or on) position as 
desired without interfering with the remaining circuit breakers in the 
panel. 
BACKGROUND OF THE INVENTION 
Many types of circuit breaker lockout devices are known in the prior art. 
Some have a locking mechanism on the door of a distribution panel. Others 
have a locking device for an individual circuit breaker. 
Presently, there are O.S.H.A. regulations (Regulations 1910.145 and 1910 
Subpart s) which require the presence of a safety padlock alone or a 
special scissors with a padlock locked thereto for locking out individual 
circuit breakers when one or more repair or maintenance persons work on 
the circuit being locked out. The number of circuit breaker lockout 
devices in the prior art that are designed to be locked out with a padlock 
alone or with the special scissors and a padlock is very limited. 
For example, in U.S. Pat. No. 4,467,152, Gordy discloses a circuit breaker 
lockout assembly which includes a bent pin arrangement (elements 5 and 6 
in FIG. 1 of Gordy). The bent pin arrangement must be inserted into 
element 10 in two pieces during assembly. The two pieces are then welded 
together, but the weld is a weak spot in the assembly. The scissors (hasp 
7) must be perpendicular to the face of the circuit breaker, as shown in 
FIG. 3. The combined weight of the hasp 7 and padlock 8 (with up to six 
padlocks) exert a large amount of torque on the elements 5 and 6 and on 
the handle of the circuit breaker. Furthermore, this arrangement of the 
hasp 7 and padlock 8 is very bulky and prevents closure of the door of the 
distribution panel. 
In other prior art, in U.S. Pat. No. 4,897,515, Zubar et al disclose the 
use of a padlock to lock out distribution panel circuit breakers. The 
Zubar et al device needs to have precision forming to insure that the 
mating pieces will match, and any deformation of the two mating pieces 
renders this device useless. The blocking member of the device (element 16 
in FIG. 1 of Zubar et al) can easily be bent out of position allowing 
undesired operation of the circuit breaker. Furthermore, some of the newer 
circuit breakers have a shallower shoulder than depicted in the Zubar et 
al patent (element 28 in FIG. 1), and the device may slip over the 
shoulder allowing unwanted and hazardous operation of the circuit breaker. 
Also, a screwdriver or other tool is necessary to install the Zubar et al 
device. 
SUMMARY OF THE INVENTION 
Accordingly, it is a primary object of the present invention to provide a 
circuit breaker lockout device that easily permits installation of a 
padlock alone or a special scissors with a padlock to conform to O.S.H.A. 
regulations. 
Another object of the invention is to provide a circuit breaker lockout 
device that avoids the creation of large amounts of torque forces on the 
lockout device when a padlock alone or special scissors with a padlock are 
installed on the lockout device. 
Another object of the invention is to provide a circuit breaker lockout 
device that does not require installation of two separate parts on the 
circuit breaker that need to be welded into a unified part once the two 
parts have been installed on the circuit breaker. 
Another object is to provide a circuit breaker lockout device that is not 
easily defeated once it is installed on the circuit breaker. 
Still another object of the invention is to provide a circuit breaker 
lockout device that permits a door of a distribution panel to be closed 
once a padlock alone or a special scissors with a padlock are installed on 
a circuit breaker. 
An additional object of the invention is to provide a circuit breaker 
lockout device that does not require the use of any tool to install the 
lockout device. 
Additional objects, advantages, and novel features of the invention will be 
set forth in part in the description that follows and in part will become 
apparent to those skilled in the art upon examination of the following or 
may be learned with the practice of the invention. The objects and 
advantages of the invention may be realized and attained by means of the 
instrumentalities and combinations particularly pointed out in the 
appended claims. 
To achieve the foregoing and other objects, and in accordance with the 
purposes of the present invention as described herein, an improved circuit 
breaker lockout assembly is provided. The lockout assembly of the 
invention is used with a certain type of circuit breaker that has an upper 
housing wall having an aperture through which the free end of the switch 
handle of the circuit breaker projects. The aperture in the upper housing 
wall has a width and a length sufficient to permit the free end of the 
switch handle to move from an on to an off position and vice versa. The 
aperture includes along its length a non-grooved portion and a number of 
grooves which, in effect, widen the width of the aperture at the grooves 
by the width of the grooves. There is a clearance space under the upper 
housing wall adjacent to the aperture. 
For the type of circuit breaker described above, the lockout assembly of 
the invention includes first means (a first main element) for engaging a 
first portion of the upper housing wall and second means (a second main 
element) for engaging a second portion of the upper housing wall. 
More specifically, the first means for engaging a first portion of the 
upper housing wall (the first main element) includes: a groove entering 
first foot for entering the grooves of the aperture; means, connected to 
the first foot, for blocking switch handle motion; and a wall connected to 
the switch handle motion blocking means. The wall also includes a first 
hole which is to be placed in registration with a second hole as described 
below. 
Aside from entering the groove, the first foot also slides under a first 
portion of the upper housing wall in a portion of the clearance space 
under the upper housing wall adjacent to the aperture and engages the 
first portion of the upper housing wall. 
The second means for engaging a second portion of the upper housing wall 
(the second main element) includes a second foot for entering the 
non-grooved portion of the circuit breaker housing aperture and for 
sliding under the second portion of the upper housing wall, in a portion 
of the clearance space under the upper housing wall adjacent to the 
aperture. A main body portion is connected to the second foot and includes 
a second hole. A handle is connected to the main body portion, and by 
moving the handle, the second hole is moved into registration with the 
first hole. Simultaneously, the handle moves the second foot away from the 
groove entering first foot and into engagement with the second portion of 
the upper housing wall. 
The second main element also includes a guide pin for riding in a 
complementary guide channel in the first main element. The guide pin and 
guide channel guide the movement of the second main element with respect 
to the first main element and the circuit breaker. 
When the first hole and the second hole are in registration, they are 
capable of receiving a shank or jaws of a locking device which prevents 
the groove entering first foot and the second foot from disengaging from 
engagement with the first portion and the second portion of the upper 
housing wall, respectively, whereby a switch-throwing motion of the 
circuit breaker switch handle is prevented. 
Still other objects of the present invention will become readily apparent 
to those skilled in this art from the following description, wherein there 
is shown and described a preferred embodiment of this invention. Simply by 
way of illustration, the invention will be set forth in part in the 
description that follows and in part will become apparent to those skilled 
in the art upon examination of the following or may be learned with the 
practice of the invention. Accordingly, the drawings and descriptions will 
be regarded as illustrative in nature and not as restrictive.

DETAILED DESCRIPTION 
With reference to the drawings, and more particularly to FIG. 1, there is 
disclosed an exploded perspective view wherein the separated components 
are first main element 11, second main element 13, and roll pin 15. When 
the separated components are assembled in accordance with the assembly 
lines shown in FIG. 1, the lockout assembly 10 of the invention is 
obtained as shown in FIG. 2. The first main element 11 is fabricated from 
a single piece of material, such as a single piece of metal (brass) or 
plastic. Similarly, the second main element 13 is fabricated from a single 
piece of material, such as a single piece of metal (brass) or plastic. The 
motion guiding roll pin 15 is made from a sheet metal. After element 13 is 
inserted between walls 56 and 58 of element 11, small hole 17 in element 
13 is placed in registration with guide channels 60 in the walls 56 and 
58. Then, one end 19 of the roll pin 15 is passed through the following 
elements in the order specificed: guide channel 60 in wall 56; small hole 
17 in element 13; and guide channel 60 in wall 58. Roll pin 15 is firmly 
retained in element 13, and the respective ends of the roll pin 15 ride in 
the respective guide channels 60. No welding is required to install the 
roll pin in the second main element 13. 
Referring to both FIGS. 1 and 2, the lockout assembly 10 is for locking a 
circuit breaker 12 in a selected off or on position. The off position is 
shown in FIG. 2. The circuit breaker 12 has a switch handle 14 with a free 
end. The circuit breaker 12 has an upper housing wall 16 which has an 
aperture (e.g., a slot) 18 through which the free end of the switch handle 
14 projects. The aperture 18 has a width 20 and a length 22 sufficient to 
permit the free end of the switch handle 14 to move from an on to an off 
position and vice versa. The aperture 18 includes along its length 22 a 
non-grooved portion 24 and a number of grooves 26 perpendicular to its 
length which, in effect, widen the width 20 of the aperture 18 at the 
grooves 26 by the width of the grooves 26. There is a clearance space 28 
under the upper housing wall 16 adjacent to the aperture 18. 
The lockout assembly 10 includes the first main element 11 for engaging a 
first portion 30 of the upper housing wall 16. More specifically, the 
first main element 11 includes groove entering first foot 32 for entering 
the grooves 26 of the aperture 18, for sliding under a first portion 30 of 
the upper housing wall 16 in a portion of the clearance space 28 under the 
upper housing wall 16 adjacent to the aperture 18, and for engaging the 
first portion 30 of the upper housing wall 16. The first foot 32 includes 
rear flanges 39 for guiding the first foot 32 into a groove 26 in the 
circuit breaker 12 housing wall 16. 
The first main element 11 also includes switch-handle-motion blocker 
portion 34, connected to the groove entering first foot 32. The first main 
element 11 also includes two opposing walls 56 and 58 connected to the 
switch-handle-motion blocker 34. The walls 56 and 58 lie in parallel 
planes. The walls 56 and 58 include first holes 38 and 43, respectively. 
Each of the two opposing walls 56 and 58 includes a respective guide 
channel 60 for receiving respective ends of the motion guiding roll pin 15 
and for guiding motion of the second main element 13. 
The two opposing walls 56 and 58 include a bottom portion 45 and a top 
portion 47. The bottom portion 45 is located near the upper housing wall 
16 when the lockout assembly 10 is installed on the circuit breaker 12. 
The two opposing walls 56 and 58 include flat upper surfaces 49. 
Each of the two opposing walls 56 and 58 includes a bar member 74 
projecting from a respective opposing wall, in the respective plane of the 
respective opposing wall. The bar members 74 serves to straddle (see FIG. 
4) and to contact the switch handle 14 in the event that the lockout 
assembly 10 is twisted while on the circuit breaker 12. In this way, the 
bar members 74 prevent the lockout assembly 10 from being twisted off of 
the circuit breaker 12. 
The main body portion 44 (see FIG. 1) of element 13 includes guide flange 
76 for sliding upon the flat upper surfaces 49 of element 11, whereby the 
second main element 13 is supported by the two opposing walls 56 and 58 of 
element 11. 
The respective guide channels 60 in the respective walls 56 and 58 of 
element 11 include first vertical portions 62 located at the respective 
bottom portion 45 of the opposing walls 56 and 58. The first vertical 
guide channel portions 62 serve to guide the second foot 42 of element 13 
into engagement with the second portion 31 of the upper housing wall 16 
when the handle 46 is moved in the direction toward the second portion 31. 
As the handle 46 is moved from the position shown in FIG. 3 to the 
position shown in FIG. 4, the ends of the guide pin 15 move in the first 
vertical guide channel portions 62 from the position shown in FIG. 3 to 
the position shown in FIG. 4. 
The guide channels 60 also include first horizontal portions 66 connected 
to respective ends of the respective first vertical guide channel portions 
62 and project horizontally therefrom. The first horizontal guide channel 
portions 66 serve to guide the second main element 13 away from the 
circuit breaker 12 subsequent to disengagement of the second foot 42 from 
the second portion 31 of the circuit breaker 12 housing wall 16. Also, the 
first horizontal guide channel portions 66 serve to guide the second main 
element 13 toward the circuit breaker 12 prior to moving the second foot 
42 into engagement with the second portion 31 of the circuit breaker 12 
housing wall 16. 
The guide channels 60 also include second vertical portions 68 connected to 
respective upper ends of the respective first horizontal guide channel 
portions 66, and the guide channels 60 also include second horizontal 
portions 70 connected to respective ends of the respective second vertical 
guide channel portions 68. The second horizontal guide channel portions 70 
serve to receive the ends of the motion guiding roll pin 15 and to retain 
element 13 above the upper housing wall 16 when element 11 is firstly 
engaged with or secondly disengaged from the first portion 30 of the upper 
housing wall 16. 
During installation of the lockout assembly 10 on the circuit breaker 12, 
the second foot 42 enters the non-grooved portion 24 of the aperture 18 
and is slid under the second portion 31 of the upper housing wall 16 in a 
portion of the clearance space 28 under the upper housing wall 16 adjacent 
to the aperture 18. The second main element 13 also includes a main body 
portion 44 connected to the second foot 42. The main body portion 44 
includes a second hole 48. The second main element 13 includes a handle 46 
connected to the main body portion 44. The handle 46 serves a dual 
purpose. The handle 46 is used to move the second hole 48 into 
registration with the first hole 38 and to move the second foot 42 away 
from the groove entering first foot 32 and into engagement with the second 
portion 31 of the upper housing wall 16. 
As shown in FIG. 3, the lockout assembly 10 of the invention shown in FIG. 
2 has been brought into contact with the upper wall 16 of the circuit 
breaker 12. As shown in FIG. 3, the first foot 32 and the second foot 42 
lie outside the plane in which the bottom side 33 of the wall 16 lies. 
More specifically, the first foot 32 and the second foot 42 lie in the 
clearance space 28 under the bottom side 33 of the wall 16. 
As shown in FIG. 4, the lockout assembly 10 of the invention shown in FIG. 
3 has been installed on the wall 16. More specifically, the leading ends 
of the first foot 32 have been pushed into engagement with portions 30 of 
the bottom side 33 of the wall 16. The leading end of the second foot 42 
has been pushed into engagement with portion 31 of the bottom side 33 of 
the wall 16. Now, in FIG. 4, the first hole 38 and the second hole 48 are 
in registration. 
As shown in FIG. 5, when the first hole 38 and the second hole 48 are in 
registration, they are capable of receiving a shank 50 of a locking device 
54 which prevents the groove entering first foot 32 and the second foot 42 
from disengaging from engagement with the first portion 30 and the second 
portion 31 of the upper housing wall 16, respectively, whereby a 
switch-throwing motion of the circuit breaker 12 switch handle 14 is 
prevented. 
More specifically, the locking device 54 is a special scissors 54 required 
by O.S.H.A. regulations whose shank 50 passes through the registered holes 
38, 48, and 43. The other shank 53 of the special scissors 54 also passes 
through the registered holes 38, 48, and 43. The special scissors 54 has a 
plurality of holes 63 and 65, to accommodate different padlocks, perhaps 
having shanks of various outer diameters. Different padlocks are used by 
different repair or maintenance personnel. Thus, when the special scissors 
54 required by O.S.H.A. regulations has provision for a plurality of 
padlocks, a plurality of repair or maintenance personnel can work on the 
same circuit protected by the circuit breaker simultaneously. Padlock 37 
is installed in hole 65. It is noted that the special scissors 54 and the 
padlock 37 are hanging vertically and are substantially coplanar with the 
plane in which the registered holes 38, 48, and 43 reside. 
With the hanging of the special scissors 54 and the padlock 37, relatively 
small torque forces are exerted on the lockout assembly 10 and on the 
circuit breaker 12. 
Because the hanging special scissors 54 and padlock 37 provide such a low 
profile, a door for a circuit breaker distribution panel (not shown) would 
be permitted to close even with lockout assembly 10 of the invention, the 
special scissors 54, and the padlock 37 installed on a circuit breaker in 
the panel. 
When installed on the circuit breaker 12, with holes 38, 48, and 43 locked 
in registration, the lockout assembly 10 of the invention is strongly 
engaged with the respective first portions 30 and second portion 31 of the 
upper housing wall 16. In this respect, it would be very difficult to 
remove the lockout assembly 10 from the circuit breaker 12 without doing 
serious damage to the circuit breaker 12. Thus, the lockout assembly 10 of 
the invention is not easily defeated. 
Furthermore, it is clear from the description above, once the component 
parts shown in FIG. 1 are assembled into the lockout assembly 10 of the 
invention shown in FIG. 2, no tools are needed to install a lockout 
assembly 10 of the invention on to remove a lockout assembly 10 from a 
circuit breaker 12. 
In accordance with another aspect of the invention, the housing wall 
aperture 18 and grooves 26 lie in a plane. As shown in FIG. 3, there is a 
predetermined first distance 77 in the plane between the top of a groove 
and the bottom of the aperture 18. The groove entering first foot 32 of 
the first main element 11 and the second foot 42 of the second main 
element 13 have respective bottom sides that are capable of being located 
in a common plane. The groove entering first foot 32 and second foot 42 
are dimensioned such that, when the respective bottom sides of the groove 
entering first foot 32 and the second foot 42 are in a common plane, there 
is a predetermined second distance 79 in the plane between one end of the 
groove entering first foot 32 and an opposite end of the second foot 42. 
The second distance 79 can be greater than the first distance 77 (although 
this relationship is not shown in the drawings), and, in order to install 
the groove entering first foot 32 under the first portion 30 of the upper 
housing wall 16, the second foot 42 needs to be raised out of and above 
the common plane with the groove entering first foot 32 before attempting 
to install the first foot 32. 
Although the lockout assembly of the invention can be used with any 
suitable circuit breaker, it is especially useful for locking a high 
voltage circuit breaker in a selected switch positiion. More specifically, 
the lockout assembly of the invention can be used on a Westinghouse, 
Series C, Industrial Circuit Breaker, e.g., Model HFD 65k, designed for 
480 volt applications and rated at 100 AMPS at 600 VAC. 
Numerous benefits result from employing the principles of the invention. 
With the invention, a circuit breaker lockout device is provided that 
easily permits installation of a padlock alone or a special scissors with 
a padlock on a circuit breaker to conform to O.S.H.A. regulations. By 
employing the invention, a circuit breaker lockout device is provided that 
avoids the creation of large amounts of torque forces on the lockout 
device when a padlock alone or special scissors with a padlock are 
installed on the lockout device. 
With the invention, a circuit breaker lockout device is provided that does 
not require installation of two separate parts on the circuit breaker that 
need to be welded into a unified part once the two parts have been 
installed on the circuit breaker. Also, with the invention, a circuit 
breaker lockout device is provided that is not easily defeated once it is 
installed on the circuit breaker. By employing the invention, a circuit 
breaker lockout device is provided that permits a door of a distribution 
panel to be closed once a padlock alone or a special scissors with a 
padlock are installed on a circuit breaker. Still further, with the 
invention, a circuit breaker lockout device is provided that does not 
require the use of any tool to install the lockout device. 
The foregoing description of the invention has been presented for purposes 
of illustration and description. It is not intended to be exhaustive or to 
limit the invention to the precise form disclosed. Obvious modifications 
or variations are possible in light of the above teachings. The embodiment 
was chosen and described in order to best illustrate the principles of the 
invention and its practical application to thereby enable one of ordinary 
skill in the art to best utilize the invention in various embodiments and 
with various modifications as are suited to the particular use 
contemplated. It is intended that the scope of the invention be defined by 
the claims appended hereto.