Abstract:
A circuit breaker includes a housing, a fixed contact mounted in the housing, a pivot member arranged in the housing, and a pivoting arm moveably mounted in the housing. The pivoting arm includes a moveable contact. The pivoting arm is rotatable about and translatable relative to the pivot member to selectively engage and disengage the fixed and moveable contacts.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The subject matter disclosed herein relates to the art of circuit breakers and, more particularly to a circuit breaker having a floating moveable contact. 
         [0002]    A circuit breaker includes one or more stationary contacts and one or more moveable contacts that are connected to close a circuit to pass electrical current. In the event that the electrical current exceeds predetermined parameters, such as during a short circuit event, the moveable contact(s) is/are shifted away from the stationary contact(s) to open the circuit. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0003]    According to one aspect of an exemplary embodiment, a circuit breaker includes a housing, a fixed contact mounted in the housing, a pivot member arranged in the housing, and a pivoting arm moveably mounted in the housing. The pivoting arm includes a moveable contact. The pivoting arm is rotatable about, and translatable relative to, the pivot member to selectively engage and disengage the fixed and moveable contacts. 
         [0004]    According to another aspect of an exemplary embodiment, a pivoting arm for a circuit breaker includes a body including a first end, a second end, and an intermediate portion, and a slot formed in the intermediate portion. The slot is defined by a wall portion. The pivoting arm is rotatable about, and translatable relative to, a pivot member. 
         [0005]    According to yet another aspect of an exemplary embodiment, a method of shifting a pivoting arm of a circuit breaker includes pivoting the pivoting arm about a pivot member between an open position and a closed position, and translating the pivoting arm relative to the pivot member. 
         [0006]    These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0007]    The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
           [0008]      FIG. 1  is a partial cross-sectional view of a circuit breaker, in accordance with an exemplary embodiment, shown in an open configuration; and 
           [0009]      FIG. 2  is a partial cross-sectional view of a circuit breaker, in accordance with an exemplary embodiment, shown in a closed configuration. 
       
    
    
       [0010]    The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0011]    A circuit breaker, in accordance with an exemplary embodiment, is indicated generally at  2 , in  FIG. 1 . Circuit breaker  2  includes a housing  4  that supports a first or line connector  6  and a second or load connector  8 . Of course, it should be understood that the relative location of the line connector and the load connector may vary. It should also be understood that connections, e.g., line connections and load connections, may vary depending upon installation, preference, and custom. Specifically, line connector  6  may receive a load connection, and load connector  8  may receive a line connection. 
         [0012]    Circuit breaker  2  includes a first or stationary contact  14  which, in the exemplary embodiment shown, is electrically connected to load connector  8 . Circuit breaker  2  also includes a second or pivoting arm  16  provided with a contact  17  electrically connected to line connector  6 . As will be detailed more fully below, pivoting arm  16  may pivot and translate about a pivot member  18  between an open configuration ( FIG. 1 ) and a closed configuration ( FIG. 2 ). More specifically, pivot member  18  establishes a rotational axis (not separately labeled) for pivoting arm  16 . More specifically, circuit breaker  2  includes a toggle  20  that may cause pivoting arm  16  to connect with, and disconnect from, stationary contact  14  through a clip  22  coupled to a spring  23 . Circuit breaker  2  also includes a de-activation member  24 . De-activation member  24  extends from a first end portion  26 , to a second end portion  28  that acts upon pivoting arm  16 . As will be discussed more fully below, de-activation member  24  pivots about a pin  29  to shift pivoting arm  16  away from stationary contact  14 . More specifically, in the event of an over-current condition, a solenoid  30  is activated causing a plunger  33  to extend outward and contact de-activation member  24  which, in turn, engages with and causes pivoting arm  16  to move away from stationary contact  14  opening an electrical circuit. 
         [0013]    In further accordance with an exemplary embodiment, a biasing member  40 , shown in the form of a flat spring  42 , urges pivoting arm  16  into contact with stationary contact  14 , as will be detailed below. Biasing member  40  includes a first leg  44  that extends to a second leg  45  through a bend or curved portion  46  that wraps about a fulcrum member  48 . First leg  44  abuts an inner surface (not separately labeled) of housing  4  while second leg  45  engages with pivoting arm  16 . Specifically, a biasing force created in second leg  45  via fulcrum member  48  acts upon pivoting arm  16 , as will be detailed more fully below. Specifically, biasing member  40  provides at least two benefits to the exemplary embodiment. Biasing member  40  advantageously urges pivoting arm  16  toward pivot member  18  and also provides a force that maintains contact between pivoting arm  16  and stationary contact  14 . 
         [0014]    In accordance with an aspect of an exemplary embodiment, pivoting arm  16  includes a body  60  having a first end  62 , a second end  64  ( FIG. 2 ) and an intermediate portion  66 . Contact  17  is provided at first end  62 . Contact  17  selectively engages with stationary contact  14 . Second end  64  includes a trip member  70  and a manual activation/de-activation element  72 . Trip member  70  extends generally, perpendicularly outwardly from body  60  and provides an interface with a trip mechanism (not shown) that reacts to an input which may be provided from a bi-metallic strip (also not shown). Trip member  70  is acted upon by the trip mechanism to move pivoting arm  16  away from stationary contact  14  in the event of, for example, an over-current condition. Manual activation/de-activation element  72  cooperates with clip  22  and toggle  20 . In this manner, toggle  20  may be manipulated to manually shift pivoting arm  16  between an open configuration ( FIG. 1 ) and a closed configuration ( FIG. 2 ). Pivoting arm  16  also includes a first outer edge  78  and a second outer edge  79  that extend between first and second ends  62  and  64  on opposing sides of intermediate potion  66 . 
         [0015]    In further accordance with an exemplary embodiment, pivoting arm  16  includes a slot  84  formed in intermediate portion  66 . Slot  84  is defined by a wall portion  88  that includes a first or curvilinear end section  90  and a second end section  94  open at first outer edge  78 . Slot  84  operably receives pivot member  18  and not only allows for rotation, but also translation of pivoting arm  16 . Slot  84  establishes an opening or discontinuity in outer edge  78  of pivoting arm  16 . 
         [0016]    Pivoting arm  16  also includes a de-activation surface  96  that may take the form of a recess  97  formed in first outer edge  78  at slot  84 , and a biasing member contact surface  100  provided at second outer edge  79 . 
         [0017]    In accordance with an exemplary embodiment, de-activation member  24  engages with de-activation surface  96  to unseat pivoting arm  16  from stationary contact  14  against a force applied to biasing member contact surface  100  by second leg  45  of flat spring  42 . Of course, it should be understood that pivoting arm  16  may also be shifted through operation of toggle  20 . Toggle  20 , acts upon activation/de-activation element  72  through clip  22  to rotate pivoting arm  16  away from stationary contact  14  against the force applied to biasing member contact surface  100 . In this position, electrical current may not flow between line connector  6  and load connector  8 . Pivoting arm  16  may also shift to a closed configuration, through rotation of toggle  20 , in which first end  62  engages with stationary contact  14  allowing electrical current to flow between line connector  6  and load connector  8 . 
         [0018]    In yet still further accordance with an exemplary embodiment, when in a closed configuration as shown in  FIG. 2 , curvilinear end section  90  is spaced from pivot member  18 . Over time, first end  62  may wear as a result of connecting and breaking a flow of electrical current. As wear occurs, pivoting arm  16  may translate further toward stationary contact  14 . Specifically, curvilinear end section  90  of slot  84  may move toward pivot member  18  under an influence of the force applied by flat spring  42 . Translation may occur over time and until such a time as curvilinear end section  90  rests upon pivot member  18 . In this manner, circuit breaker  2  may continue to operate despite changes in surface characteristics of first end  62  and/or stationary contact  14 . 
         [0019]    At this point it should be understood that the exemplary embodiments describe a circuit breaker having a pivoting arm that both rotates about, and translates relative to, a pivot member. The pivoting arm includes a slot that facilitates the translation to accommodate wear in a contact surface(s). A benefit of the present invention lies in the incorporation of a biasing member, which may take the form of a flat spring, that urges the pivoting arm toward the pivot member and also provides a force that maintains contact between pivoting arm and a stationary contact. It should also be understood that the exemplary embodiments provide a system that allows the pivoting arm to adjust for tip wear/erosion and maintain a desired contact pressure over an overall, extended, service life of the circuit breaker. Further, the pivoting arm coupled with the biasing member, in accordance with the exemplary embodiments, ensures continued contact pressure while also achieving a reduction in parts, a simplification in an overall construction, and a reduction/elimination in potential failure points. 
         [0020]    While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.