Abstract:
An apparatus for releasably securing a plurality of arc plates in an arc extinguishing chamber or arc stack. The arc stack includes a plurality of arc plates separated by an air gap. The arc plates slide into a slot in the arc stack housing. A stop member and a locking tab position and secure the arc plate in the housing. The arc plate engages the spring-like stop member and the locking tab, which restrain the arc plate from moving or vibrating after being locked in place.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    Not Applicable 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002] Not Applicable 
     
    
     
       BACKGROUND OF THE INVENTION  
       Field of Invention  
         [0003]    This invention pertains generally to arc stacks in electrical switches. More particularly, this invention pertains to an apparatus for housing and securing arc plates.  
         BRIEF SUMMARY OF THE INVENTION  
         [0004]    An apparatus for housing and securing a plurality of arc plates in an arc extinguishing chamber or arc stack is provided. The apparatus includes a latching mechanism that positively locks the arc plates, which are included in a switch arc stack for an electrical switch. Each of a plurality of arc plates in the arc stack are inserted in a slot defined by securing ledges extending from securing members or side walls. The arc stack slots have a rear stop that prevents the arc plate from being pushed through the stack and the slot has a locking tab that, when it returns to its normal position after the arc plate is inserted into the slot, positions and positively secures the arc plate in the stack. The rear stop and locking tab are resilient and apply force against the arc plate, preventing the arc plate from vibrating in the arc stack housing.  
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0005]    The above-mentioned features of the invention will become more clearly understood from the following detailed description of the invention read together with the drawings in which:  
         [0006]    [0006]FIG. 1 is a perspective view of a arc stack housing for the arc plates;  
         [0007]    [0007]FIG. 2 is a cutaway view of the arc stack housing and one arc plate;  
         [0008]    [0008]FIG. 3 is a perspective cutaway view of the arc stack housing; and  
         [0009]    [0009]FIG. 4 is a perspective view of an arc plate. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0010]    An apparatus for housing and securing an arc plate in a arc extinguishing chamber or arc stack is disclosed. An arc stack includes a housing containing a plurality of arc plates.  
         [0011]    [0011]FIG. 1 illustrates an arc stack housing such as can be used in any blade type electrical switch. Those skilled in the art will recognize that arc stacks are used in many types of switches and the present invention is not limited to arc stacks having the illustrated configuration.  
         [0012]    The illustrated arc stack housing  102  includes two substantially parallel housing walls  112  and  114 . In the illustrated embodiment, the housing walls  112  and  114  are secured to each other in a spaced relationship by an upper member  116  and a lower member  316  (FIG. 3). The upper member  116  includes a longitudinal notch  118  that corresponds with the notches  404  in the arc plates  402  (FIG. 4). The lower member  316  has a longitudinal notch  318  that corresponds with the notches  404  in the arc plates  402 . These notches,  118 ,  318  and  404 , allow the switch blade (not illustrated) to pass freely through the arc stack. Also illustrated, in general, are protrusions  122  and  124  that are used for attaching and securing the arc stack housing  102  inside the switch. Those skilled in the art will recognize that the configuration of the arc stack housing  102  can vary to meet the configuration of the switch into which the arc stack is used without departing from the spirit and scope of the present invention.  
         [0013]    [0013]FIG. 2 is a cut-away plan view showing the inside face of one wall  112 . FIG. 3 is a cut-away perspective view showing the inside face of one wall  112 . FIG. 2 illustrates a section of a fully installed arc plate  402  in the lowermost position and a partially installed arc plate  402 ′ in the adjacent upper position. FIG. 4 illustrates an arc plate  402 , which has a leading end  418  with a notch  404 , a pair of longitudinal edges  412  and  414 , and a trailing end  416 . FIGS. 2 and 3 illustrate five slots  216 , and each slot  216  is adapted to receive an arc plate  402 . Those skilled in the art will recognize that the number of slots  216  can vary without departing from the spirit and scope of the present invention.  
         [0014]    The arc stack housing  102  includes members for securing a plurality of arc plates  402  in the housing  102 . Referring to FIGS. 2 and 3, a number of generally parallel securing ledges  210  protrude from the housing wall  112 . Each securing ledge  210  defines a lower surface  212  and an upper surface  214 . The opposed upper surface  214  and lower surface  212 ′ of the generally parallel securing ledges  210  and  210 ′ define slots  216  into which the arc plates  402  slide. The longitudinal edge  412  of the arc plate  402  is adjacent to the housing wall  112  when the arc plate  402  is inserted into the slot  216 . The slot  216  for receiving the uppermost arc plate  402  is defined by a space between the upper member  116  and the upper surface  214  of the uppermost securing ledge  210 .  
         [0015]    At one end of the slot is a stop member  218  that engages the leading edge  418  of the arc plate  402 . The stop member  218  is resilient and deforms in the longitudinal direction of the slot  216 , that is, the stop member  218  has shape memory whereby it is biased back toward its original shape when the deforming force is removed. At the opposite end of the slot  216  is a resilient locking arm  224  having a locking tab  222  that engages the trailing end  416  of the arc plate  402  when the arc plate  402  is fully installed in the slot  216 . The locking arm  224 ′ resiliently deforms away from the opposed lower surface  212 ″ when the arc plate  402 ′ is inserted into the slot  216 ′, thereby ensuring that the locking tab  222 ′ does not impede the arc plate  402 ′ as it is being inserted into the slot and being positioned in the housing  102 . When the arc plate  402  is positioned and secured in the slot  216 , the locking tab  222  engages the trailing end  416  of the arc plate  402 , which is forced against the locking tab  222  by the stop member  218 ′, and the locking arm  224  exerts a force against the arc plate  402 , forcing the arc plate  402  against the opposed lower surface  212 ′.  
         [0016]    The opposing surfaces of the stop member  218  and the locking tab  222  are separated by a distance that is less than the distance between the leading end  412  and the trailing end  416  of the arc plate  402 . When the arc plate  402  is positioned and secured in the housing  102 , the stop member  218 ′ is deformed in the longitudinal direction away from the arc plate  402 , and the stop member  218 ′ exerts a longitudinal force against the arc plate  402 .  
         [0017]    Although FIGS. 2 and 3 illustrate only one-half of the arc stack housing  102 , the illustrated structure is mirrored on the other half. Those skilled in the art will recognize that either one or two stop members  218  and either one or two locking tabs  222  can be used to position and secure the arc plates  402  without departing from the spirit and scope of the present invention.  
         [0018]    In the illustrated embodiment, the arc stack housing  102 , including the lower ledge surface  212 , the upper surface  214 , the resilient rear stop  218 , the locking tab  222  and the locking arm  224 , is a molded assembly with the elements integrally molded together. With this embodiment, fabrication of the arc stack requires only that the arc plates  402  be inserted and secured in the arc stack housing  102 . Additionally, the spring action of the locking arm  224  and the spring action of the rear stop  218  serve to capture and prevent the arc plate  402  from vibrating in the housing  102 .  
         [0019]    From the foregoing description, it will be recognized by those skilled in the art that an apparatus for securing the arc plates in an arc stack has been provided. The arc stack housing is fabricated of an insulating material and the arc plates are fabricated of a conducting material. The arc plates are positioned in slots in the arc stack during fabrication. The integral locking mechanism secures the arc plates after the plates are fully inserted into the housing.  
         [0020]    While the present invention has been illustrated by description of several embodiments and while the illustrative embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant&#39;s general inventive concept.