Circuit interrupter with non-symmetrical terminal collar

A molded case circuit breaker having separable main contacts and an operating mechanism utilized to cause the separable main contacts to open and close. A trip unit is provided to actuate the operating mechanism in desirable circumstances. The circuit breaker has external terminals which are connectable with an external load and an external power supply. A collar is used to interconnect the circuit breaker terminals with the load and power supply. The terminal collar in this case is non-symmetrical. The non-symmetrical collar provides two functions: the first function is that the path of electrical continently between adjacent collars is enlarged for higher voltage applications because of the non-symmetrical nature of each collar; secondly, the circuit breaker case has a seat therein which has the same cross-section as the non-symmetrical collar, so that the collar can only be inserted therein in one cross-sectional orientation.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The subject matter of this invention is related generally to molded case 
circuit breakers and more specifically to terminal collars for molded case 
circuit breakers. 
2. Description of the Prior Art 
Molded case circuit breakers are well known in the ar t as exemplified by 
U.S. Pat. No. 5,910,760 issued Jun. 8, 1999 to Malingowski et al., 
entitled "Circuit Breaker with Double Rate Spring" and assigned to the 
assignee of the present application. The foregoing is incorporated herein 
by reference. 
Molded case circuit breakers include a set of separable main contacts, one 
of which is usually fixed and one of which is movable for automatically 
opening upon the occurrence of an overload or short circuit electrical 
current in the network which the circuit breaker is provide to protect. 
The separable main contacts are opened as a result of the functioning of a 
latched operating mechanism, which is interconnectable by way of an 
operating handle to a region outside of the circuit breaker. The operating 
handle may be used to trip the circuit breaker manually or to reset and 
close the circuit breaker contacts once they have been opened 
automatically. The reset action is required because circuit breakers must 
be mechanically charged to be in a state to reopen immediately upon 
closure in the event that the fault which cause the tripping in the first 
place has not disappeared. The reset action charges the circuit breaker 
for that purpose. Molded case circuit breakers have trip units, which are 
often removably insertable in the circuit breaker case. The trip unit in 
addition has at least two calibratable functions, one of which is 
generally identified as thermal tripping and the other of which is 
generally identified as magnetic tripping. The trip unit includes a 
rotatable trip bar, which when rotated will actuate a latchable tripping 
operation within the operating mechanism to automatically open the circuit 
breaker contacts. The rotatable trip bar is usually actuated in one of two 
ways. The first way is in response to what is called a magnetic tripping 
of the circuit breaker. This occurs when the amount of current flowing 
through the separable main contacts of the circuit breaker is so high as 
to represent a potential catastrophic failure and which therefore requires 
exceedingly quick opening action of the circuit breaker. In such a case a 
electron magnetic core, which produces magnetic flux in proportion to the 
amount of electrical current flowing through the separable main contacts 
attracts a movable armature, the movement of which eventually causes the 
trip bar to move to thus cause the tripping action. The second tripping 
occurrence is in response to a relatively low amount of overload current, 
which eventually will cause overheating of the electrical wires in the 
circuit to be protected, but which does not necessitate the instantaneous 
action a short circuit requires and thus does not require the magnetic 
action spoken of previously. In this case a bi-metal element is heated by 
a heater element which conducts the electrical current flowing through the 
separable main contacts. As the bi-metal element flexes or moves it 
impinges upon the tripping bar causing it to flex and move 
correspondingly, until eventually a point is reached in which the tripping 
bar causes the circuit breaker to unlatch and trip automatically. Both the 
magnetic trip mechanism and the thermal trip mechanism usually require 
initial calibration. 
In one half of an AC cycle, the electrical current flows through the 
circuit interrupter from the load by way of a terminal collar to the load 
terminal of the circuit breaker and from there into the trip unit where it 
flows through the previously mentioned heater which in turn is serially 
connected to the electron magnetic member of the magnetic trip device. 
From there it is interconnected by way of a flexible cable to one end of a 
moveable contact arm and from there to the main contact on the moveable 
contact arm. When the contact arm is closed, it is closed upon a fixed 
contact which is supported usually on u-shaped conductor, which in turn is 
interconnected with a line terminal and there to the line terminal collar 
and finally to the electrical line. In addition the circuit breaker 
usually has an arc chute for assisting in diminishing the electrical arc 
drawn between the separating contacts during the opening operation for 
extinguishing of the arc. The circuit breaker also has a slot motor 
arrangement, which is utilized to interact magnetically with the 
electrical current flowing in the opening contact arm to accelerate the 
opening of the contact arm magnetically. The operating mechanism usually 
consists of a series of levers and linkages, which are interconnected with 
the separable main moveable contact arm, the handle mechanism, and by way 
of a latch arrangement with the aforementioned trip bar. Description and 
operation of all of the above may be found in the previous mentioned, 
incorporated by reference '760 patent. 
Molded case circuit breakers usually have collars which interface the line 
and load terminals of the circuit breaker with electrical cables. Such a 
collar may be found in U.S. Pat. No. 5,206,789 issued Apr. 27, 1993 to 
Barbry et al., entitled "Terminal Assembly for a Circuit Breaker and 
Similar Apparatus" and assigned to the assignee of the present 
application. Other examples of such arrangements may be found in U.S. Pat. 
No. 5,005,104. In the past these collars have been basically symmetrical 
in nature. That it is, the functions, equally well in a number of 
orientations. It would be advantageous, however, if a collar could be 
found which had the same interconnection and electrical isolation facility 
as the previous collars, but which could be reduced in size to thus allow 
the size of the overall breaker to be reduced. It would be further 
advantageous if the circuit breaker casing was adapted to having this 
collar integrated into it. 
SUMMARY OF THE INVENTION 
In accordance with the invention there is provided a circuit interrupter 
having a housing. There is an operating mechanism disposed within the 
housing. Also, separable contacts are disposed within the housing in 
cooperation with the operating mechanism for being opened by the operating 
mechanism, a terminal is interconnected with the separable contacts for 
providing an electrical conduction path from a region outside of the 
housing to the separable contacts. The terminal has a non-symmetrically 
shaped terminal collar connected thereto with a region of relatively 
smaller dimension relative to a region of relatively larger dimension, the 
closest uninsulated path between the non-symmetrically shaped terminal 
collar and the nearest external portion of the housing being from the 
region of relatively smaller dimension.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings and FIGS. 1 through 4 in particular, there is 
shown a molded case circuit breaker or interrupter 10 having a main base 
12 and primary cover 14. Attached to the primary cover 14 is a secondary 
cover 16. A handle 18 extends through a secondary escutcheon 22A in the 
secondary cover 16 and aligned primary escutcheon 22B in the primary cover 
14. An operating mechanism 20 is interconnected with the handle 18 for 
opening and closing separable main contacts in a manner which will be 
described hereinafter. This circuit breaker has a line end 15 and load end 
17. The circuit breaker or interrupter includes a removable trip unit 24. 
Removable trip unit 24 has an underlapping lip 24X, the purpose of which 
will be described hereinafter. There are also depicted a load terminal 26, 
a right side accessory region or pocket 27 and a left side accessory 
pocket or region 31. 
Referring now more specifically to FIGS. 2, 3 and 4, there are depicted a 
separable movable contact 28 disposed upon a moveable contact arm 32 and a 
fixed contact 30 disposed upon a fixed contact support or u-shaped member 
34. Line terminal 36 is disposed to the left in FIG. 2, for example, at 
the line end 15 of the circuit interrupter in a terminal cave or pocket 
29. A load terminal 26 is disposed to the right in FIG. 2, for example, in 
a load terminal cave or pocket 29. To the left on the line terminal 36 is 
disposed a line terminal collar 38 which will be described in more detail 
hereinafter, and to the right is provided a load terminal jumper-tomovable 
contact arm conductor 802. Connected to conductor 802 is a flexible 
conductor 39, which is interconnected with movable contact arm 32 as shown 
schematically. The load terminal jumper or frame conductor 802 is 
interconnected at its other end with a bi-metal heater 180, which in turn 
is interconnected at its other end with the terminal 26. Consequently, 
when the circuit interrupter separable main contacts 28 and 30 are closed 
upon each other, there is a complete circuit through the circuit 
interrupter from right to left starting with line conductor 26 through 
bi-metal heater 180, through load terminal jumper or frame conductor 802, 
through flexible conductor 39, through the movable contact arm 32, through 
contact 28 to contact 30 and from there through the fixed contact support 
or u-shaped member 34 to line terminal 36. 
There is provided a operating mechanism 20 for assisting in opening and 
closing the separable main contacts 28 and 30. In particular, the 
operating mechanism includes a cradle 52, which is pivoted on one end at a 
cradle fixed pivoted pin 54 by way of an opening 54A in the cradle for 
placement of the cradle fixed pivoted pin therein. The cradle includes a 
cradle-to-side accessory region side protrusion 55. There is provided an 
upper toggle link 46 and a lower toggle link 48. They are joined pivotally 
by an upper and lower toggle link pin 50. There is provided a lower toggle 
link to movable contact arm main pivot assemble attachment pin 56, which 
is affixed to the movable contact arm 32 at an opening 56A. There is also 
a cradle to upper toggle link pivot pin 58, by which the upper toggle link 
46 is placed in physical contact with the cradle 52. There is also 
provided a movable contact arm main pivot assembly 59, which movably, 
rotatably pivots on a pivot 60. There is also provided a primary frame 
latch 62 which operates or rotates on a primary frame latch pivot 64. The 
primary frame latch 62 cooperates with a secondary frame latch 68, which 
rotates on a secondary frame latch pivot 70. The operating power for the 
tripping operating of the circuit breaker is provided by a charged main 
toggle coil spring 72. The main toggle coil spring is interconnected with 
a handle yoke 44 by way of a handle yoke attachment post 45. The other end 
of the spring 72 is attached to the toggle link pin 50. Cradle 52 has a 
cradle lip 73, which is captured or held in place by the primary latch 62 
when the separable main contacts 28 and 30 are closed. No tripping of the 
circuit breaker can take place by way of the operating mechanism until the 
aforementioned primary frame latch 62 has been actuated away from the 
cradle lip 73 in a manner which will be described hereinafter. There is 
provided a combination secondary-frame-latch-primary-frame-latch torsion 
spring 78, which exerts force against both latches sufficient to cause 
appropriate movement thereof at the appropriate time. The secondary frame 
latch has a laterally extending trip protrusion 79, the purpose of which 
will be described later hereinafter. Actuation of the primary and 
secondary frame latches occurs exclusively by way of the utilization of a 
resetable trip unit trip plunger 74, which is contained entirely within 
the removable trip unit 24. The trip unit trip plunger 74 is controlled or 
latched by way of a plunger latch or interference latch 75. The secondary 
frame latch 68 is in disposition to be struck by the moving trip unit 
plunger abutment surface 288. Upon opening of the separable main contacts 
30 and 28, an electric arc is drawn therebetween which is exposed to an 
arc chute 77. The secondary frame latch 68 has a bottom portion 89, upon 
which is disposed an arcuate stop surface 90 for the primary frame latch 
62. There is also provided above that arcuate stop surface and as part of 
the acruate stop member a latch surface 92. 
The operating mechanism described herein may be the same as found in U.S. 
Pat. No. 5,910,760 issued Jun. 8, 1999 to Malingowski et al., entitled 
"Circuit Breaker with Double Rate Spring". Thought the primary and 
secondary frame latches are disposed within the case 12, the trip unit 
plunger 75 is responsible for initiating all tripping action from the trip 
unit 24 into the region of the secondary latch 68. Alternatively, the 
secondary latch 68 may be actuated by a push-to-trip button in a manner, 
which will be described hereinafter. The secondary latch 68 is actuated to 
rotate to the left as shown in FIGS. 2, 3 and 4, for example, in direction 
81 about its pivot 70. As this occurs the acruate stop surface 90 for the 
secondary frame latch 68 rotates away from the bottom of the primary frame 
latch 62 until the lateral latch surface 92 rotates into a disposition to 
allow the bottom of the primary frame latch 62 to rotate to the right 
under the force of the cradle 72. This causes the primary frame latch 62 
to clear the lip 73 of the cradle 52 to allow the cradle 52 to rotate 
upwardly about its pivot 54 in a direction 82 under the power of the now 
collapsing coil spring 72 by way of the force exerted thereupon by the 
upper toggle link 46 acting against the cradle-to-upper-toggle link 
connecting pin 58. As the toggle spring 72 relaxes, the upper and lower 
toggle links collapse, which in turn causes the lower toggle link to 
movable contact arm pivot assembly 56 to rotate upwardly in the direction 
86 about its pivot 60. This, of course, causes the contact arm 32 to 
rotate similarly in the direction 88, thus opening the separable main 
contacts 28 and 30 and in most cases establishing an electrical arc of 
conducting electrical current there across. The action of the secondary 
frame latch 68 can be duplicated by causing secondary latch push-to-trip 
member side laterally extending trip protrusion 79 to rotate in the 
direction 81 by operation of a push-to-trip member which will be described 
later hereinafter. Resetting of the circuit breaker is accomplished in a 
matter well known in the prior art and described and shown with respect to 
the aforementioned U.S. Pat. No. 5,910,760. The important part of the 
operation with respect to this feature is the movement of the secondary 
frame latch point 76 in the direction opposite to direction 82, against 
the plunger face 288 in a manner, which will be described later 
hereinafter. However, if movement of the plunger face 288 in the rightward 
direction against its plunger spring, as will be described hereinafter, is 
prevented because of the latching of the plunger member 74, in a manner 
which will be described hereinafter, then the circuit breaker can not be 
reset. An important feature of the invention lies in the fact that the 
ultimate control of the resetting of the circuit breaker and tripping of 
the circuit breaker can be accomplished only from the removable trip unit 
24, rather than from the operating mechanism 20. 
An embodiment of the invention is shown in FIGS. 5 through 11. In 
particular there is shown in FIG. 5 a non-symmetrical aluminum terminal 
collar 700. The aluminum terminal collar 700 has a main body 710 with a 
transverse cable opening 712. There is provided a cable compression 
fastener 714, which has threads and which may be threaded downwardly into 
a similarly threaded hole 726 to abut any cables (not shown) which have 
been transversely fed through the hole or opening 712. An appropriate 
drive opening 716 is provided in the member 714 for screwing it down into 
the hole 716. There is provided a threaded hole 724 in the bottom of the 
main body 710 of the terminal 700 into which a threaded a line terminal 
securement nut 718 may be upwardly threaded therein, through a portion of 
the circuit breaker case (not shown). There is provided a lateral terminal 
cut-out 722 on the bottom of the terminal main body 710 for alignment with 
line conductor, such as will be described hereinafter. The terminal 
securement nut 718 may be driven or threaded into hole 724 by way of 
suitable through drive hole 720. The main body 710 has a pair of main body 
beveled surfaces on the right and left at 728 and 730, respectively. There 
is also a rear transverse main body surface at 732 and a front parallel 
transverse main body surface 733, which abuts and is between the beveled 
regions 728 and 730. 
Referring to FIG. 6, a non-symmetrical steel terminal collar 750 embodiment 
of the invention is depicted. There is a main body 752 of the steel 
terminal collar 750, having a first side 754, a top 756, a second and 
parallel side to the first side 758 and bottom 760. There is a lower 
movable cable compression plate 762, which is disposed within the 
perimeter of the aforementioned sides, top and bottom and is movable up 
and down therein for compressing cables against an upper movable 
compression plate 763, which is oppositely disposed from the lower one. 
There is provided a locking tab 764, which fits into a hole or opening 
764A in side 758 for completely securing the top 756 of collar to the side 
758 of the collar. There is provided a threaded cable compression bolt 
766, which may be driven downwardly through a complimentary threaded hole 
768 in the top 756 of the main body 752. A threaded rider member 770 is 
disposed on the bottom thereof and it links up with a threaded hole or 
opening 763A in the movable upper cable rider member 763. There is 
provided on the left and right, beveled shoulders 772 and 774, 
respectively, which correspond to the beveled regions 730 and 728 
respectively, for example, in the embodiment of FIG. 5. By referring to 
FIG. 2, it can be seen that the steel body terminal 750 may be utilized as 
a line terminal 750B and as a load terminal 750A. 
FIGS. 7 and 8 show the disposition of the members 700 and 750 on terminals 
36 of u-shape members 34 with the fixed contact 30. Insulation 715M 
disposed between the contact 30 and the terminal 36 in each case. 
Referring now to FIGS. 9 and 10, in FIG. 10, there is shown at 76 a 
complimentary pocket seat in the circuit breaker case 12 for seating 
either of the collar embodiments therein. Because the seat 776 is 
non-symmetrical having bevels on the front but not on the back, the 
terminals can only be seated therein in one direction or one orientation, 
which is a feature of the present invention. Another feature of the 
present invention lies in the enhanced voltage separation caused by the 
bevels or chamfers 728 and 730. FIG. 9 shows a prior art arrangement in 
which, prior art main body 728A is not beveled as in the present 
invention. The distance between the conductive corner 728A of the collar 
and the nearest point 12BB on the non-conductive casing 12B for the 
terminal arrangement 36B is represented by `d`. However in FIG. 10, it can 
easily be seen that the arrangement utilizing the member 700 for example, 
is such that the distance `D` between the bevel 730 for example, and the 
nearest, closest corner 12AA is significantly larger than the distance 
`d`. 
By referring to FIG. 11, it can be seen that the complimentary pocket seat 
776 in the circuit breaker case only allows a seating of either of the 
terminal arrangements 700 or 750 in one orientation within the circuit 
breaker case 12. This is another feature of the invention.