Abstract:
A combination air circuit breaker bell alarm reset and lock-out accessory unit interacts with the circuit breaker closing system to prevent charging of the circuit breaker closing spring until and unless the bell alarm module has been manually reset in one option and allows automatic reset of the bell alarm module prior to charging of the closing spring in a further option. The orientation of the bell alarm module on the combination reset and lock-out accessory unit support plate determines the reset or lock-out option selection.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of U.S. Application Ser. No. 08/908,767, filed Aug. 8, 1997, which is now U.S. Pat. No. 5,960,941. 
    
    
     BACKGROUND OF THE INVENTION 
     Air circuit breakers, as described within U.S. Pat. No. 3,095,489 entitled “Manual Charging Means for Stored Energy Closing Mechanisms of Electric Circuit Breakers” and U.S. Pat. No. 3,084,238 entitled “Ratchet Mechanism for Charging a Closing Spring in an Electric Circuit Breaker”, include operating mechanisms that are mainly exposed to the environment. Since the air circuit breakers are rated to carry up to several thousand amperes of current continuously, the exposure to convection cooling air assists in keeping the operating components within reasonable temperature limits. 
     Various accessory devices are used with such air circuit breakers to provide auxiliary function along with overcurrent protection. One such accessory is the bell alarm accessory that provides local and remote indication as to the occurrence of circuit interruption. U.S. Pat. No. 5,502,286 entitled “Bell Alarm and Lock-Out for High Ampere-Rated Circuit Breakers” describes a bell alarm accessory used with so-called “insulated case” circuit breakers wherein the circuit breaker interrupting components are completely enclosed within an insulating plastic enclosure. 
     U.S. Pat. No. 5,986,225 filed on Jun. 19, 1997 entitled “Circuit Breaker Bell Alarm Accessory with Lockout” describes a bell alarm accessory for use with a high ampere-rated air circuit breaker that provides local as well as remote indication of such circuit interruption as well as preventing circuit breaker contact closure until and unless the bell alarm accessory has been manually reset. 
     High ampere-rated air type circuit breakers operate in the range of 2500 to 5000 amperes such that the large circuit breaker operating components are arranged air type circuit breakers, that operate in the range of 150 to 1500 amperes, require bell alarms with lockout function to prevent contact closure until the bell alarm unit is reset, the arrangement of the circuit breaker smaller operating components do not allow the use of the high ampere-rated bell alarm reset accessory. 
     U.S. Pat. No. 6,054,661 entitled “Circuit Breaker Bell Alarm Accessory with Lockout Function” filed concurrently with this application describes a low ampere-rated air circuit breaker that includes an arrangement for preventing the circuit breaker contacts from becoming closed until the bell alarm module has become manually reset. U.S. Pat. No. 6,242,703, dated Jun. 5, 2001 B1, entitled “Circuit Breaker Bell Alarm Accessory with Automatic Reset for Small Frame Air Circuit Breaker” filed concurrently with this application further describes an arrangement for automatically resetting the bell alarm accessory within a low ampere-rated air circuit breaker during the early stage of the circuit breaker closing spring charge cycle. 
     One approach to an arrangement that allows alternative bell alarm automatic reset function reset or bell alarm lock-out function within one accessory apparatus within high ampere-rated air circuit breakers is found in U.S. Pat. No. 5,960,941 filed Aug. 8, 1997 entitled “Circuit Breaker Bell Alarm Accessory with Both Automatic Reset and Lock-out Function”. 
     In view of the size and component design differences between the high ampere-rated and low ampere-rated air circuit breakers described earlier, the high ampere-rated combined bell alarm accessory would not function within low ampere-rated air circuit breaker enclosures. The purpose of the instant invention is to describe an arrangement for allowing selection between bell alarm automatic reset and automatic lock-out function in low ampere-rated air circuit breakers. 
     SUMMARY OF THE INVENTION 
     A combination bell alarm lock-out and bell alarm automatic reset accessory unit alternatively interacts with the circuit breaker closing system to prevent charging of the circuit breaker closing spring until and unless the bell alarm module has been manually reset in one option and interacts with the circuit breaker closing system to automatically reset the bell alarm accessory during charging of the circuit breaker closing spring in another option. The combination accessory support plate includes a first aperture to allow the bell alarm lockout plunger to interact with a first part of the closing system for automatic reset and includes a second aperture to allow the bell alarm lockout plunger to interact with a second part of the closing system to prevent closure of the circuit breaker closing spring until the bell alarm accessory is reset. The position of the bell alarm accessory on the accessory support plate determines which of the two apertures within which the lockout plunger becomes inserted. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is top perspective view of an air circuit breaker containing the combined bell alarm automatic reset and automatic lock-out accessory unit attached to a front part of the circuit breaker contact closing assembly in accordance with the invention; 
     FIG. 2 is an enlarged side plan view of an air circuit breaker an air circuit breaker depicting a bell alarm lock-out accessory unit; 
     FIG. 3 is an enlarged side plan view of an air circuit breaker depicting a bell alarm automatic reset accessory unit; and 
     FIGS. 4 a  and  4   b  are front perspective views wherein FIG. 4 a  is shown configured for automatic lock-out function and FIG. 4 b  is shown configured for automatic reset function of the combination bell alarm reset and lock-out accessory unit within the air circuit breaker of FIG. 1 with the bell alarm accessory module in isometric projection. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The air circuit breaker  10  of FIG. 1 is shown attached to the circuit breaker cover plate  13  interfacing with the circuit breaker contact closing assembly  11  that is positioned between the circuit breaker operating mechanism sideframes  12 . Circuit breaker operating mechanism sideframes  12  are similar to that described within the aforementioned U.S. Pat. No. 3,095,489. The circuit breaker cover  14  supports the trip unit programmer  15 . Trip unit programmer  15  is similar to that described in U.S. Pat. No. 4,672,501 entitled “Circuit Breaker and Protective Relay Unit”. The circuit breaker cover  14  includes buttons  16  for releasing the circuit breaker contacts (not shown) to their OPEN condition and for moving the contacts to their CLOSED condition. The circuit breaker operating handle  18 , positioned within the handle recess  19 , allows manual interaction with the contact closing assembly  11  to both open and close the circuit breaker contacts. An accessory such as a bell alarm module  21 , which is similar to that described in the aforementioned U.S. Pat. No. 5,502,286, is mounted on a combined bell alarm reset and lock-out unit  22  to provide visual indication of the occurrence of contact separation by means of the pop-up target  20  that extends through the target aperture  9  formed in the circuit breaker cover  14 . Other circuit breaker accessories can be inserted within the accessory recess  17 , if so desired. 
     Referring to FIG. 2, circuit breaker  10  illustrates an automatic lock-out facility. Circuit breaker cover  14  (see FIG. 1) is removed from the circuit breaker cover plate  13  to illustrate the position of the bell alarm module  21  on the bell alarm lock-out unit  32 . Bell alarm module  21  is arranged on the bell alarm support plate  24  with the bell alarm reset plunger  31  extending through the lock-out aperture  30  formed in the cover plate  13 . In the contact CLOSED condition, the bell alarm target  20  is un-extended from the bell alarm module  21  and becomes extended therefrom upon occurrence of contact separation during circuit overload conditions. The bell alarm support plate  24  is fastened to the cover plate  13  by means of mounting studs  29  and the lockout slide  43  is attached to the bottom of the support plate  24  for interaction with the contact closing assembly  11  in the manner described in the aforementioned U.S. Pat. No. 6,054,661. The closing lever  27  is attached to the closing shaft  39  within the closing mechanism described therein interacts with the operational links  38  in the manner described below. The closing lever  27  has a cam surface  27 B at one end of the closing lever  27  that interacts with a post  40 A on the closing shaft cam  40 . A tab  27 A is captured within the slot  43 A on the lockout slide  43  next to the bell crank assembly at the other end thereof. The purpose of the bell alarm lock-out function is to insure that the bell alarm module  21  is manually reset by depression of the bell alarm target  20  with the corresponding retraction of the plunger  31  from within the lockout aperture  30 . 
     Referring to FIG. 3, circuit breaker  10  illustrates an automatic reset facility. Circuit breaker cover  14  (see FIG. 1) is removed from the circuit breaker cover plate  13  to illustrate the position of the bell alarm module  21  on the bell alarm reset unit  22 . Bell alarm module  21  is arranged on the bell alarm support plate  24  with the bell alarm reset plunger  31  extending through the reset aperture  28  formed in the cover plate  13 . The bell alarm unit  21  is depicted in FIG. 3 with the circuit breaker  10  in the OFF condition such that the pop-up target  20  on the bell alarm module  21 , as indicated in phantom, is extended from the top and the lock-out plunger  31  is extended from the bottom thereof through the reset aperture  28  in the manner described within the aforementioned U.S. Pat. No. 6,242,703B1, dated Jun. 5, 2001. The closing lever  27  extending from the closing shaft  39  interacts with the operating link  38  by means of the post  38 A extending from the operating link in contact with tab  27 C on the end of the closing lever  27 . The reset bypass cam  26  interacts with the reset arm  35  by contact between the roller  36  on reset arm  35  and the surface  26 A formed on the bottom of the reset bypass cam  26 . 
     When an attempt is made to rotate the closing shaft  39  to charge the circuit breaker closing spring (not shown), tab  27 A on the top of the closing lever, captured within the slot  43 A (FIG. 2) on the end of the lockout slide  43 , allows the reset arm  35  to rotate in unison with the reset bypass cam  26  by virtue of the connection or reset spring  34  whereby the tab  37  on the bottom of the reset arm  35  retracts the lockout plunger  31  from within the reset aperture  28  to allow rotation of the operating link  38  away from the operating link  42  and return the closing shaft  39  to the charged position. In the charged position of the closing shaft  39 , the post  40 A on the closing shaft cam  40  returns into contact with the cam surface  27 B formed on the end of the closing lever  27 , as shown earlier in FIG.  2 . The purpose of the bell alarm reset function is to allow automatic reset of the bell alarm target  20  by automatic retraction of the plunger  31  from within the reset aperture  28 . 
     FIGS. 4A and 4B illustrate the selection between automatic lock-out and automatic reset function within a low ampere-rated circuit breaker  10 ′. The combined bell alarm reset and lockout assembly (hereinafter “combined assembly  22 ′”) is attached onto the circuit breaker cover plate  13 . The closing shaft  39  operates within the contact closing assembly  11  between the operating mechanism sideframes  12  relative to the combined assembly  22 ′ in the same manner described earlier with respect to FIGS. 2 and 3 to provide the bell alarm lock-out and reset functions with the lock-out assembly  32  and the reset assembly  22  attached to a common support plate  24 . In accordance with the teachings of the invention, a separate pair of apertures such as the reset aperture  28  and the lock-out aperture  30  are formed within the common support plate  24 . 
     The bell alarm module  21  is depicted in phantom in two different positions prior to attaching to the combined assembly  22 ′ to illustrate the reset and lock-out function options. To insure that the pop-up target  20  is positioned accurately with respect to the bell alarm target aperture  9 , shown within the circuit breaker cover  14 , of FIG. 1, the alignment pin  44 , on the bottom of the bell alarm module  21  is therefor received in a common alignment aperture  41 . To facilitate automatic lock-out function, the plunger  31  in the bell alarm module  21  is inserted within the lock-out aperture  30 , as indicated. To facilitate automatic reset function, the plunger  31  in the bell alarm module  21  is inserted within the reset aperture  28 . If the reset bell alarm function is later required, the bell alarm module  31  is removed from the support plate  24  such that the plunger  31  is extracted from the lock-out aperture  30  and the same module is rotated to position the plunger within the reset aperture  28  so that such reset function is then automatically attained. It is shown that either lock-out function or reset function can be factory as well as field selected by simply removing the bell alarm module and rotating the module about the alignment pin  44  depending on the desired function. 
     An arrangement for bell alarm accessory function within low ampere-rated air circuit breakers has herein been described, whereby a combined assembly is adapted for receiving a common bell alarm module and the rotational position of the bell alarm module selects either a lock-out function or a reset function.