Abstract:
According to a preferred embodiment, a terminal for electrical leads comprises a housing, a guide, a current bar, a leaf spring and a moveable operator. The guide is supported by the housing and comprises guide surfaces that connect with at least one surface of the current bar. The leaf spring comprises at least one limb with an offset for clamping a cable to the current bar. Additionally, the terminal comprises a moveable operator dimensioned and configured to allow the release of a cable from contact with the current bar.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The subject matter described herein relates generally to a device for screwless fitting of terminal leads in electrical applications, more particularly in circuit breakers. 
   2. Related Art 
   Terminals for electrical leads are typically found in various applications including switches and circuit breakers. 
   Prior art methods of connecting lead wire to the circuit breaker required screwing the wire to the terminal, which resulted in a loss of efficiency. More particularly, it increased the amount of installation time required for connecting wire to circuit breakers. Therefore, screwless terminals such as the one described in U.S. Pat. No. 7,224,140 comprise spring clips that hold electrical leads to the terminal. The spring clips are comprises various shapes including U shapes and are made of flexible material. Currently, a simplified insertion and release mechanism is lacking to connect both flexible and/or hard wires to a terminal. 
   Accordingly, there is a need to provide an improved terminal for electrical leads to provide for a more efficient installation of devices such as circuit breakers. 
   SUMMARY OF THE INVENTION 
   According to one embodiment, a terminal for electrical leads comprises a housing, a guide, a current bar, a leaf spring and a moveable operator. The guide is supported by the housing and comprises guide surfaces that connect with at least one surface of the current bar. The leaf spring comprises at least one limb with an offset for clamping a cable to the current bar. Additionally, the terminal comprises a moveable operator dimensioned and configured to allow the release of a cable from contact with the current bar. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings are described herein: 
       FIG. 1  is a perspective view of a modular electric device as per the invention, has a screwless cable terminal arrangement. 
       FIG. 2  is an exploded view of the screwless cable terminal components. 
       FIG. 3  is a perspective view of the guide. 
       FIG. 4  is a perspective view of the current bar. 
       FIG. 5  is a perspective view of the leaf spring. 
       FIG. 6  is a perspective view of the operator. 
       FIG. 7  is a perspective view of the one embodiment of the invention during cable inserting condition. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   One embodiment of the present inventions concerns a screwless terminal arrangement for connecting rigid or flexible electric wires to a circuit breaker. 
   Referring now to  FIG. 1 , a circuit breaker in accordance with one embodiment of the present invention is illustrated generally at  10 . The circuit breaker  10  is shown as having an insulation housing  1  containing an operating element  2 . The insulation housing  1  is provided with at least one terminal compartment  4 , in which is disposed a current bar  3 , and a clamping spring  5 . 
   In one embodiment of the invention, the housing  1  is constructed of an injection-molded polymer. Additionally, the housing  1  comprises a rectangular shape with a cavity for holding the components of the circuit breaker  10 . The housing contains a surface  8  with an aperture  7  to allow the push-in surface of the operator  2  to project out of the housing  1  to enable an installer to press it in order to insert or release a cable  50  from the hold of the leaf spring  5 . Similarly, the housing  1  has a surface  9  with an aperture  6  for insertion of the cable  50  into the circuit breaker that is perpendicular to the surface  7  wherein the aperture for the operator  2  is located. The surface  9  comprises a single aperture  6  that allows the insertion of one cable  50  into the circuit breaker. Alternately, the surface  9  comprises two separate apertures that can receive a single cable  50  each. The housing  1  further contains a flat surface area within the cavity of the housing  1  onto which the terminal flange  20  will anchor. Furthermore, the housing cavity has a base surface that supports the guide  4 . 
   Referring now to  FIG. 2 , the components of the screwless terminal are shown in an exploded view. 
   Referring now to  FIG. 3 , the guide or terminal compartment  4  is shown. The terminal compartment  4  acts as a support and/or guide for the electric wires that are inserted through the housing  1 . The guide has two outer surfaces  30  that are configured to interlock with the current bar  3 . The outer surfaces  30  guide the operator  2  to the leaf spring. The base surface has an aperture for holding with the leaf spring  5 . The guide  2  can be made of any resilient material and is substantially rectangular in shape. 
   Referring now to  FIG. 4 , the current bar  3  is shown. The current bar  3  is a component that forms a current path from an externally inserted wire  50  to the inner portion of the circuit breaker. The current bar  3  has surfaces  21  for connecting to the electric wire  50 . One embodiment of the invention includes a current bar  3  that is substantially rectangular in shape with the base having an aperture through which the operator  2  moves to make contact with the spring  5 . Furthermore, the current bar  3  includes two surfaces that interconnect with two surfaces of the guide  4 . The current bar  3  further comprises a flange  20  that anchors to the housing  1 . Additionally, the current bar  3  comprises a conductive, resilient material. 
   Referring now to  FIG. 5 , the spring element  5  is depicted as a flat leaf spring angled in such a position to facilitate easy insertion and self-locating of the cable  50  while inserting the cable  50  in the opening  6  provided on the circuit breaker. The spring  5  leaf can have a U-shape with a base  41 , a side  40  comprising an angled tab to interlock with the fixed terminal  4 , and two clamping limbs  42 . The spring element  5  can be angled to allow the free end of its clamping leg  42  to form a curved flange, that serves as a clamping edge  43  for holding the electric wire  50  inserted in the connection position as well as a surface for contact with the operating mechanism  2  for re-opening the terminal. Additionally, the free end of the spring element  5  exerts sufficient pressure to hold the inserted cable  50  against the terminal  4  to allow for the current flow. The spring  5  is designed to hold a single cable  50  in place when connecting a second, rigid cable  50  by pushing towards the terminal  4 . The previously inserted rigid or flexible cable  50  will be continuously clamped by the spring  5  and will not come out. 
   Referring now to  FIG. 6 , the operator  2  is a component required for cable  50  release during re-opening of the terminal  4  connection. The operator has wing-like flanges  16 ,  17  that guide the operating member  2  to move in a vertical direction while arresting other degrees of freedom. The operating element  2  is operated with a push-in action. An embodiment of the invention includes an operator  2  that is a solid component. The operator can include two rectangular flanges  16  that span perpendicular to another set of flanges  17  of a lesser width to which a foot portion  18  is connected and comprises the bottom surface of the operator  2 . The foot portion comprises two perpendicular surfaces that are wider than the portion of the operator  2  to which they are connected. The bottom surface of the operator  2  engages the leaf spring limbs  42 . 
   To insert a rigid cable  50 , the installer can push the exposed, rigid cable  50  through the aperture  6  towards the current bar  3 . The installer can press the operating mechanism/release button  2  and pull the cable  50  to release the cable  50 . When a flexible cable  50  is used for insertion, an installer will be required to push the exposed portion of the flexible cable  50  towards the terminal  4  by pressing the operating mechanism/release button  2 . The installer will be required to press the operating mechanism  2  and pull the cable  50  to release the cable  50  from the terminal  4 . 
   Referring now to  FIG. 7 , a view of an embodiment of the invention is shown in relation to wires  50  ready for insertion into terminal  4  through aperture  6 . 
   While the present invention has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the present invention is not limited to these herein disclosed embodiments. Rather, the present invention is intended to cover all of the various modifications and equivalent arrangements included within the spirit and scope of the appended claims.