Circuit breaker closing and opening interlock assembly

This invention relates to a high ampere-rated circuit breaker which meets the electrical code requirements of the world market. The closing springs controlling the CLOSED state and the opening springs controlling the OPENED state of the circuit breaker contacts are interlocked to prevent operation of both springs at the same time. The closing lever and the opening lever interact in such a manner that only one of the levers can release the associated closing or opening springs.

BACKGROUND OF THE INVENTION 
U.S. Pat. No. 4,001,742 entitled "Circuit Breaker Having Improved Operating 
Mechanism" describes a circuit breaker capable of interrupting several 
thousand amperes of circuit current at several hundred volts potential. As 
described therein, the operating mechanism is in the form of a pair of 
powerful operating springs that are restrained from separating the circuit 
breaker contacts by means of a latching system. Once the operating 
mechanism has responded to separate the contacts, the operating springs 
must be recharged to supply sufficient motive force to the movable contact 
arms that carry the contacts. 
U.S. Patent Application entitled "Operating mechanism for high ampere-rated 
circuit breaker" application Ser. No. 08/202,140 filed Feb. 25, 1994, 
describes an operating mechanism capable of immediately resetting the 
circuit breaker operating mechanism to reclose the contacts without having 
to recharge the circuit breaker operating springs immediately after 
opening the circuit breaker contacts. 
U.S. Patent Application entitled "Rating module unit for high ampere-rated 
circuit breaker" application Ser. No. 08/203,062 filed Feb. 28, 1994, 
describes a circuit breaker closing spring modular unit whereby the 
circuit breaker operating springs are contained within a separate unit 
from the operating mechanism and can be installed within the circuit 
breaker enclosure without disturbing the operating mechanism assembly, 
U.S. Patent Application entitled "Handle operator assembly for high 
ampere-rated circuit breaker" (41PR-7130) describes a handle operator unit 
capable of generating large spring charging forces by means of an 
externally-accessible manually operated handle. A ratchet and pawl 
assembly allows the manually-applied charging forces to be applied to the 
operating springs. Once the circuit breaker operating mechanism closing 
springs are fully-charged, some means must be employed to release the pawl 
to allow the closing springs to become fully operational. 
The charging of the powerful operating springs controlling the circuit 
breaker contacts is made manually by means of a ratchet and pawl assembly. 
A two stage latching arrangement controls the retention and release of the 
pawl to retain and discharge the operating springs as described in U.S. 
Patent Application entitled "Latching arrangement for high ampere-rated 
circuit breaker operating springs" application Ser. No. 08/218,287 filed 
Mar. 28, 1994. 
Since separate pairs of operating springs are used to close and to open the 
circuit breaker contacts, it is important to prevent any attempt to close 
and open the circuit breaker contacts simultaneously. 
Prior attempts to discourage depressing the closing and opening buttons 
that were externally accessible included remotely positioning the buttons 
from each other on the circuit breaker cover. However, with the 
streamlined operating mechanism described within the aforementioned U.S. 
Patent Applications, the operating mechanism components interact with the 
accessories that are mounted within the circuit breaker cover next to the 
electronic trip unit. To efficiently couple the operating mechanism 
components with the accessories and with the electronic trip unit, it is 
preferable to arrange the closing and opening buttons alongside each 
other. 
One purpose of the invention is to provide an interlock arrangement between 
the closing and opening components that responds to the closing and 
opening buttons that will reliably prevent both buttons from being 
operated simultaneously. 
SUMMARY OF THE INVENTION 
The opening and closing systems for the opening and closing springs for the 
circuit breaker contacts are interlocked to prevent both systems from 
being operated at the same time. The opening lever and closing lever 
within the associated systems interact through abutting surfaces. The 
first lever to respond moves away from the abutting surfaces allowing the 
associated opening or closing springs to respond. Simultaneous operation 
of the opening and closing buttons prevents both levers from responding.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The high ampere-rated circuit breaker 10 shown in FIG. 1 is capable of 
transferring several thousand amperes quiescent circuit current at several 
hundred volts potential without overheating. The circuit breaker consists 
of an electrically insulated base 11 to which an intermediate cover 13 of 
similar insulative material is attached prior to attaching the top cover 
14, also consisting of an electrically-insulative material. Electrical 
connection with the interior current-carrying components is made by load 
terminal straps 12 extending from one side of the base and line terminal 
straps (not shown) extending from the opposite side thereof. The interior 
components are controlled by an electronic trip unit contained within a 
recess 15 on the top surface of the top cover 14. Although not shown 
herein, the trip unit is similar to that described within U.S. Pat. No. 
2,581,181 and interacts further with an accessory contained within the 
accessory recess 16 to provide a range of protection and control functions 
such as described, for example within U.S. Pat. No. 4,801,907. The 
operating handle 17 located within the handle recess 18 allows manual 
operation of the circuit breaker operating mechanism to open and close the 
circuit breaker contacts by means of the powerful closing and opening 
springs 20, 20'. The externally-accessible closing button 27A and the 
externally-accessible opening button 31A contact and depress the 
associated closing tab 27 and opening tab 31 within the interlock assembly 
24 best seen by now referring to FIG. 2. 
The interlock assembly 24 is supported by the operating mechanism sideframe 
21, 22 next to the closing latch 23 which functions in the manner 
described within aforementioned U.S. Pat. No. Ser. No. 08/218,287 filed 
Mar. 28, 1994. The interlock assembly 24 is positioned above the drive 
shaft, which although not shown, is received within the drive shaft slots 
25 and 25A which extends between the sideframes. The closing lever 26 is 
formed from a single metal piece to define the closing tab 27 at one end 
and U-shaped pivot support 28 at an opposite end. The projection 41 
extending from the inner part of the support 28 interacts with the 
interlock tab 42 extending from one leg 35A on the interlock link 35 in 
the manner to be described below in some detail. The interlock link 35 is 
formed from a single metal piece to define a U-shaped configuration having 
two legs 35A, 35B connected by a bight 35C. A pair of thru-holes 37, 38 
formed at opposite ends of the bight receive the closing link pivot shaft 
36 which positions and supports the closing link between the sideframes 
21, 22 by means of openings 39, 40. The opening lever 30 is formed from a 
single metal piece to define the opening tab 31 at one end and U-shaped 
pivot support 32 at an opposite end. The projection 44 extending from the 
bottom of the support 32 interacts with the interlock tab 43 extending 
from the other leg 35B on the interlock link 35 in the manner to be 
described below in some detail. The common pivot 29 extends through the 
thru-holes 46-49 formed within the closing lever 26 and opening lever 30 
and the openings 33, 34 formed in the sideframes 21, 22 to position the 
closing lever 26 and opening lever 30 side-by-side as shown in FIG. 3. 
The interlock assembly 24 is assembled between the sideframes 21, 22 and is 
positioned between the closing latch 23 and the latching system 45 
depicted in phantom, as described in the aforementioned patent application 
Ser. No. 08/205,240 filed Mar. 3, 1994. The interlock link 35 supported on 
the pivot shaft 36 locates the interlock tabs 42, 43 in line with the 
closing lever 26 and opening lever 30 to insure interlock function between 
the closing and opening levers when the closing tab 27 and the opening tab 
31 are simultaneously depressed and the closing and opening levers attempt 
to rotate about the common pivot 29 extending through the U-shaped pivot 
supports 28, 32 respectively. 
The operation of the interlock assembly is best seen by referring now to 
FIGS. 4 and 5. In 4, the sideframe 21 is cut-away to show the operation of 
the opening lever 30 independent of the closing lever 26 by depressing the 
opening tab 31. The opening lever 30 rotates counter-clockwise about the 
common pivot 29 and positions the projection 44 extending from the bottom 
of the opening lever under the interlock tab 43 extending from the 
interlock link 35 which is pivotally arranged on the pivot shaft 36. This 
prevents the closing tab 27 from being depressed and the rotation of the 
closing lever 26 due to the corresponding capture of the projection 41 
extending from the closing lever 26 against the interlock tab 42 extending 
from the interlock link 35. In FIG. 5, the closing tab 27 on the closing 
lever 26 is depressed rotating the closing lever 26 counter-clockwise 
about the common pivot 29 and positions the projection 41 extending from 
the closing lever 26 over the interlock tab 42 on the interlock link 35. 
This prevents the opening tab 31 from being depressed and the rotation of 
the opening lever 30 due to the corresponding capture of the projection 44 
extending from the opening lever 30 against the interlock tab 43 extending 
from the interlock link 35. 
In the event that both the closing tab 27 on the closing lever 26 and the 
opening tab 31 on the opening lever 30 are attempted to be depressed at 
the same time, there is a race to determine which of the projections 43, 
44 on the corresponding levers will reach the associated lockout position 
first thereby preventing the other lever from rotating. Although not 
shown, the opening and closing levers, 30, 26 are spring-biased back to 
their initial starting positions as soon as the associated opening and 
closing tabs, 31, 27 are released.