Circuit breaker with increased electrical spacing

A circuit breaker in which the case comprises two half-cases abutting together to jointly form the case. A handle link includes a handle with a portion extending through the half-cases. The half-cases have abutting, interfitting tongue and groove portions to increase the creepage and clearance distances from outside the circuit breaker to the closest electrically energized parts within the circuit breaker. Further the handle link and the half-cases have a pivotally semi-circular interfitting tongue and groove connection. The abutting, interfitting tongue and groove portions of the half-cases are disposed on both sides of said semi-circular connection and pivotally adjacent thereto so as to form a tongue and groove connection at the opening of the case through which the handle extends and on either side thereof. Also, the handle link has pintles pivotally extending into recesses provided therefor in the half-cases.

BACKGROUND OF THE INVENTION 
This invention relates generally to molded case electrical circuit breakers 
of the type wherein the case is formed by two half-cases abutted together 
to jointly form the case and the meeting of a European safety standard for 
such circuit breakers by economically modifying a known case. 
With the increasing emphasis on exports so as to minimize the balance of 
payments trade deficit of our country, engineers involved in the design of 
electrical equipment for export such as circuit breakers, must design the 
equipment to comply not only with the requirements of the United States 
National Electrical Code (NEC) and of Underwriters Laboratories, Inc. 
(UL), but also of other countries. 
Guidance for design engineers can be found in the safety standards of the 
International Electro Technical Commission (IEC) and the safety standards 
set forth in the West German Verband Deutscher Elektrotechniker e.V. (VDE) 
codes. 
For circuit breakers, the IEC and VDE codes require 8 mm clearance and 
creepage distances between any operator accessible part of the circuit 
breaker and a hazardous voltage within the circuit breaker. 
This invention is directed to providing such minimum 8 mm clearance and 
creepage distances in molded case circuit breakers of existing design and 
construction with a minimum of change in the design and construction 
thereof. 
Additional information on the IEC and VDE codes may, of course, be obtained 
from the codes themselves and from an article entitled "Meeting Circuit 
Breaker Safety Standards at Home and Abroad" appearing in Design News 
issue of Sept. 21, 1981 at pages 86 to 92, inclusive. 
BRIEF SUMMARY OF THE INVENTION 
It is an object of this invention to provide a known molded case circuit 
breaker with means for increasing the clearance and creepage distances 
between any operator accessible part of the circuit breaker and a 
hazardous voltage within the circuit breaker to at least 8 mm so as to 
comply with the IEC and VDE codes. 
This invention is embodied in a circuit breaker for mounting to a panel 
comprising a case (formed by two abutting half-cases) and an 
electromagnetic device comprising a solenoid coil and an armature. The 
armature is electrically energized and the overlying portions of the 
abutting half-cases are provided with a tongue and groove construction 
which increases the clearance and creepage distances to above the required 
minimum. 
Likewise, the abutting half-cases have been modified alongside where the 
handle exits the case to provide with the handle a tongue and groove 
construction between opposite sides of the handle and the abutting 
half-case and the handle link has been pivoted solely on the adjacent 
half-cases instead of being also supported on the metal supporting frame 
plates of the previous construction. 
The previous construction is shown in U.S. Pat. No. 3,329,913, issued in 
the name of William W. Camp, but assigned to the Heinemann Electric 
Company. 
The foregoing and other objects of this invention, the principles of this 
invention, and the best modes in which I have contemplated applying such 
principles will more fully appear from the following description and 
accompanying drawings in illustration thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to the drawings, a circuit breaker 10 including a case 12 is 
illustrated in FIG. 1. The circuit breaker 10 is molded from a suitable 
electrical insulation material, as is well known, and the case 12 
comprises two substantially half-cases 14 and 16 which abut each other, as 
shown, to house the internal parts of the circuit breaker 10. The 
half-cases 14 and 16 define a suitable opening through which extends the 
handle 18 of the circuit breaker 10. Suitable terminals 22 and 24 extend 
from the case 12 to connect the circuit breaker to a suitable circuit. 
The half-cases 14 and 16 are secured together by three rivets 26 which 
extend through suitable holes in the half-cases 14 and 16. The case 12 is 
secured to a panel 30 by suitable screws 32, as is well known. 
The circuit breaker 10 includes an electromagnetic device 34 well known in 
the art, comprising a solenoid coil 36, a pole piece 37, and a metallic 
armature 38. The pole piece 37 and the armature 38 are electrically 
energized so that potentially hazardous creepage and clearance paths exist 
between the panel 30 and the closest parts of the pole piece 37 and of the 
armature 38. To increase the creepage and clearance distances the abutting 
walls 40 and 42 of the half-cases 14 and 16 overlying and embracing the 
pole piece 37 and the armature 38 are formed with a tongue 44 interfitting 
with a groove 46. The tongue 44 and groove 46 are slightly inclined or 
V-shaped, as shown, with the base of the "V" being preferably truncated 
for ease in manufacture. Thus, as shown in FIG. 2, a tortuous path is 
provided from the plane where the underside of the panel 30 abuts the case 
12 to the nearest point of either the pole piece 37 or the armature 38 
which is sufficiently long to comply with the safety standards of IEC and 
VDE, i.e., at least 8 mm in length. 
Likewise, referring to FIGS. 3 and 4, a further source of potentially 
hazardous creepage and clearance paths is the area of the abutting 
half-cases 12 and 14 abutting a link 50 with which the handle 18 is 
integral. The link 50 is provided with semicircular ribs 52 and 54 
interfitting with a mating semicircular groove 56 formed in the abutting 
wall 42 of the half-case 16 and with a mating semi-circular groove 58 
formed in the abutting wall 40 of the half-case 14, respectively, to form 
tongue and groove connections on opposite sides of the link 50. 
Further, the link 50 is formed on opposite sides with integral pintles 60 
and 62 pivotally received in mating openings or recesses 64 and 68 formed 
in the half-cases 14 and 16, as shown in FIG. 3. The lower portion 70 of 
the link 50 is connected to the toggle linkage (not shown) to actuate the 
mechanism (not shown) of the circuit breaker. 
Thus, as best understood from FIG. 4, the semi-circular ribs 54 and grooves 
58 (of the handle 18 and the half-cases 14 and 16) are disposed between 
the tongues 44 and grooves 46 of the half-cases 14 and 16 which extends 
away from the handle 18 and on either side thereof providing a tongue and 
groove type barrier and circuitous creepage and clearance paths across 
virtually the entire zone between the operator accessible part of the 
circuit breaker, i.e., the upper part of the case 12 which is fastened to 
the panel 30, and the closest electrically energized parts within the 
circuit breaker, for example, the armature 38.