Patent Document

BACKGROUND OF THE INVENTION 
     This invention relates generally to global contactors and specifically to a contact block utilizing tool free mechanisms for installation and for changing the state of individual poles. 
     A conventional electrical contactor in one form typically comprises an electromagnetically actuated device having a magnetic core proximate an armature. Typically, a coil is electrically energized to draw the armature to the magnetic core. The electromagnetically actuated device may be a control relay, a contactor, a motor starter or the like. The armature is operatively associated with a movable device such as an actuator. With an electrical switching apparatus the actuator operates a contact assembly. 
     A contact assembly may be an integral component of the electrical switching apparatus or it may be an auxiliary device to be added thereto. In either case, the contact assembly typically includes a contact having a pair of stationary contacts and a movable contact. The stationary contacts are fixedly mounted in spaced relation with one another. The movable contact is mounted to the pusher. The contact assembly may provide for normally open contact operation or normally closed contact operation. In some conventional contact designs a different geometry stationary contact is used for normally open and normally closed stationary contact. 
     A contact block may include a multitude of contacts. However, if additional contacts are required an additional contact block must be added or an auxiliary contact block is added to the end of the contact block. In this configuration the entire contact block must be removed and replaced to increase the number of auxiliary contact blocks. 
     Additionally, different variations of contact assemblies may require the availability of multiple pusher or auxiliary contact block designs based on the location and orientation of the movable contacts. For example, both contacts can be normally opened, both contacts can be normally closed, one contact can be normally open and the other normally closed. Additionally, the timing of one contact opening and the other closing can also be altered. These variations necessitate additional parts inventory resulting in loss of economies of scale. 
     The typical contact typically has either two or four poles. If additional poles are needed, a series of single pole auxiliary contacts must be assembled individually on to the contactor. Further, each pole is either normally open or normally closed from the factory. The same device cannot be used in a changed state. 
     In high voltage applications arcs of electricity crosses the gap as the contacts are closed. Each time an arc occurs carbon scarring or buildup occurs. The carbon scarring over time can reduce the reliability of the contact. 
     Accordingly, there is a need for a contact assembly for use in an electrical switching apparatus designed to facilitate ease of use, and minimize installation and inventory cost. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In one aspect, the present invention relates to an auxiliary contact block. The auxiliary contact block comprising a housing and a tool free latching mechanism. The tool free latching mechanism further comprising a stationary member integral to the housing and a latching bar. The latching bar comprising a button in communication with a moveable member by a central body. 
     In another aspect of the invention, a tool free mechanism for an auxiliary contact block comprises a first stationary member and a second moveable member. The second moveable member being in communication with a button. Pressure on the button moves the second moveable member from a first rested position to a second released position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a contact block as is known in the industry. 
         FIG. 2  is a perspective view of a 4 pole frontal block according to an aspect of the invention. 
         FIG. 3  is a perspective view of a fixation lever according to an aspect of the invention. 
         FIG. 4  is an exploded view of the 4 pole contact block of  FIG. 2  according to an aspect of the invention. 
         FIG. 5  is a cutaway view of the 4 pole contact block of  FIG. 2  showing a carrier assembly according to an aspect of the invention. 
         FIG. 6  is a perspective view of the carrier assembly of  FIG. 5  according to an aspect of the invention. 
         FIG. 7  is a perspective view of a normally open spacer according to an aspect of the invention. 
         FIG. 8  is a perspective view of a normally closed spacer according to an aspect of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     It is contemplated that the teaching of the description set forth below is applicable to electric contact blocks and auxiliary contact blocks, including but not limited to normally open, normally closed, relay, timer or a motor starter contact. The present invention is therefore not intended to be limited to any particular type of electrical contact, such as in contact  100 . Like reference numbers denote the same or similar features among the various views and figures. 
       FIG. 1  illustrates a contactor  100  as is known in the industry. The operation of a contactor is known in the industry and will not be described in detail. Contactor  100  may be any shape but generally has front  106 , back (not visible), which is opposite the front  106 , and right and left sides  104 , and  112  respectively. Above contactor  100  is a frontal block  200 . 
     Front  106  and back (not visible) comprise at least one port  102  for interconnecting wires for communication with an electric circuit. Feet  108  provide means  110  for securing contactor  100  to an enclosure by screws or bolts. A port (not shown) interfaces with a frontal block  200 . 
       FIG. 2  is a perspective view of a frontal block  200  according to an aspect of the invention. Frontal block  200  has a cover  202  over a housing  204 . Frontal block  200  is fixed to Contactor  100  by means of fixation lever  300 . Wires are connected at terminal  404  for control of external electrical circuits. 
     The fixation lever  300  of  FIG. 3  secures frontal block  200  to contactor  100 . The fixation lever  300  has protrusions  304  on either side of main body  305 . Protrusions  304  fit into channels (not shown) in the base of housing  204 . Spring body  306  is made of a flexible material and connects main body  305  with cover interface  302 . Cover interface  302  rests within a channel in housing  204 . When Frontal block is assembled with contactor, the cover interface  302  rests against the wall of pocket in contactor cover (as shown in  FIG. 3 ). By applying pressure to the top of cover interface  302  the spring body  306  flexes causing cover interface  302  to move out of the channel in housing  204  and wall in contactor cover. 
     Housing  204  accommodates a carrier assembly  400  and two terminal assemblies  405  on either side of carrier assembly  400 . Terminal assembly  405  may contain normally open terminals, normally closed terminals or a combination of either. The configuration of each is known in the art and will not be described in detail. Carrier assembly  400  interfaces with contactor  100  through the base of housing  204  via lever  424 . Motion in contactor  100  is transmitted through lever  424  causing carrier assembly  400  to move up or down in housing  204 . When at a rested state the carrier assembly  400  is generally extended into housing  204 . 
     As shown in  FIG. 5 , the frontal block may contain a pair of normally open contacts  450  and a pair of normally closed contacts  451 . For normally open contact  450  a stationary contact  401  attached to terminal assembly  405  and rests below movable contact  402 . As carrier assembly is moved from the rested position to an energized position the stationary  401  and movable  402  contacts are brought together. When the carrier assembly  400  is in the rested position the stationary  401  and movable  402  contact is offset by spacer  700 . For normally closed contacts  451  a stationary contact  431  is attached to terminally assembly  405  and rests above a moveable contact  430 . As carrier assembly  400  is moved from a rested position to an energized position the moveable contact  430  is removed from contact with the stationary contact  431 . To prevent continued contact as the carrier assembly  400  is energized a spacer  800  constrains movable contact  430 . 
     Moveable contacts  402  and  430  are set in channels  460 ,  461  and are backed by springs  422 , as shown in  FIG. 6 . The spring  422  in channel  460  is held at on end by peg  420  in carrier assembly  400  and at the other by moveable contact  402 . The spring  422  in channel  461  is held at one end by spring support  406  which sits in a groove in the housing  204  and at the other end by moveable contact  430 . Each channel  460 ,  461  may comprise a wall (not numbered) that may be inclined or angled to allow for the auto-cleaning of the contacts  402 ,  430  as they move up and down within the channels. 
       FIG. 7  is a perspective view of spacer  700 . Spacer  700  has upper protrusion  714  and lower protrusion  712 . Upper protrusion  714  is inserted into groove  414  in carrier assembly  400 . Lower protrusion  712  is inserted into grove  412  in carrier assembly  400 . The protrusions  712  and  714  located the spacer in channel  460 . 
       FIG. 8  is a perspective view of a spacer  800 . Spacer  800  has groove  816  which mates with protrusion  416  in channel  461 . 
     Each channel contains protrusions  712  and  714  as well as groove  416 . Therefore any channel  460  and  461  can accommodate either spacer. By interchanging, making removable, making reversible and/or making invertible certain parts, such as the contacts  402  and  430  and the spacers  700  and  800 , a normally open contact may become normally closed or a normally closed may become normally open absent use of any tools. 
     For example, to switch from normally open to normally closed, spacer  800  is removed and spacer  700  is inserted. The spring  422  is moved from the upper position proximate to peg  420  to a lower position supported by spring support  406 . Moveable contact  402  is flipped to be in position of moveable contact  430 . Stationary contact  401  is replaced with stationary contact  431 . By reversing the process a normally closed contact will become normally open. 
     While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.

Technology Category: 5