Abstract:
An electrical contactor has a removable coil comprising a contactor housing including a cavity. A pair of fixed coil terminals are mounted to the contactor housing proximate the cavity. A removable coil is removably mountable in the cavity. A pair of coil terminal clips are mounted to the coil. The fixed coil terminals make electrical contact with the coil terminal clips when the removable coil is inserted in the cavity.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority to, and incorporates by reference herein in its entirety, pending U.S. Provisional Patent Application Ser. No. 60/507,066 (Attorney Docket No. 2003P15061US), filed 29 Sep. 2003 and pending U.S. Provisional Patent Application Ser. No. 60/506,837 (Attorney Docket No. 2003P15050US), filed 29 Sep. 2003. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to an electromechanical device having a removable coil and, more particularly, to a system and method for connecting a removable coil to fixed coil terminals.  
       BACKGROUND OF THE INVENTION  
       [0003]     A conventional electrical switching apparatus in one known form comprises an electromagnetically actuable 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 and the like. The armature is operatively associated with a moveable device such as an actuator. With an electrical switching apparatus, the actuator operates a contact assembly.  
         [0004]     The coil typically comprises a bobbin or the like carrying one or more windings. Opposite ends of the winding(s) are electrically connected to coil terminals fixedly mounted to the encapsulated coil. The coil terminals typically include screws for connecting wires to external control circuits that control operation of the device.  
         [0005]     Some electrical switching apparatus include a removable coil. The coil might be removable to change voltage or if there has been coil burn out or the like. With a conventional removable coil, including integral fixed coil terminals, control wiring must first be removed prior to removal of the coil. Upon replacement of the coil, the terminal wiring must then be reconnected.  
         [0006]     The present invention is directed to improvements in electromechanical devices.  
       SUMMARY OF THE INVENTION  
       [0007]     In accordance with the invention, there is provided a system and method for connecting a removable coil to fixed coil terminals.  
         [0008]     Broadly, there is disclosed a system for connecting a removable coil to a fixed coil terminal in an electrical device. The system comprises a housing and a fixed coil terminal mounted to the housing. A removable coil is removably mountable in the housing. A coil terminal clip is mounted to the coil. The fixed coil terminal makes electrical contract with the coil terminal clip when the removable coil is inserted in the housing.  
         [0009]     It is a feature of the invention that the coil terminal clip restrains movement of the removable coil in the housing.  
         [0010]     It is another feature of the invention that the coil terminal clip comprises a clamp terminal that resiliently clamps to the fixed coil terminal. The clamp terminal may comprise an enlarged opening for aligning with the fixed coil terminal. The fixed coil terminal may comprise a planar blade. The clamp terminal can clamp against planar surfaces of the blade or peripheral edges of the blade.  
         [0011]     It is a further feature of the invention that the coil terminal clip comprises a leaf spring.  
         [0012]     It is another feature of the invention that the coil terminal clip comprises a bifurcated clip.  
         [0013]     It is yet another feature of the invention that the fixed terminal comprises a spring loaded terminal for biasing against the coil terminal clip.  
         [0014]     It is yet a further feature of the invention that the coil terminal clip comprises a spring.  
         [0015]     There is disclosed in accordance with another aspect of the invention an electrical contactor having a removable coil comprising a contactor housing including a cavity. A pair of fixed coil terminals are mounted to the contactor housing proximate the cavity. A removable coil is removably mountable in the cavity. A pair of coil terminal clips are mounted to the coil. The fixed coil terminals make electrical contact with the coil terminal clips when the removable coil is inserted in the cavity.  
         [0016]     There is disclosed in accordance with another aspect of the invention a method for connecting a removable coil to a fixed coil terminal in an electromechanical device comprising: providing a housing; extending a fixed coil terminal from the housing; providing a removable coil; extending a coil terminal from the coil; and inserting the removable coil into the housing wherein the coil terminal clip engages with and clamps on to the fixed coil terminal to electrically connect the removable coil to the fixed coil terminal.  
         [0017]     Further features and advantages of the invention will be readily apparent from the specification and from the drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]      FIG. 1  is a perspective view of a contactor having a removable coil in accordance with the invention;  
         [0019]      FIG. 2  is a perspective view, similar to  FIG. 1 , illustrating installation of a coil and magnet in the contactor;  
         [0020]      FIG. 3  is a perspective view of the coil and coil terminal clips prior to encapsulation;  
         [0021]      FIG. 4  is a partial, perspective view illustrating the removable coil proximate fixed coil terminals prior to insertion;  
         [0022]      FIG. 5  is a view similar to  FIG. 4  illustrating the removable coil connected to the fixed coil terminals;  
         [0023]      FIG. 6  is a partial perspective view illustrating the coil terminal clip of  FIG. 3  with lead in edges to align the coil terminal to fixed terminals;  
         [0024]      FIG. 7  is a partial perspective view similar to  FIG. 6 , illustrating a clamp terminal formed in a different orientation;  
         [0025]      FIG. 8  is a partial perspective view illustrating a coil terminal in the form of a leaf spring;  
         [0026]      FIG. 9  is a partial perspective view of an alternative embodiment illustrating a fixed terminal comprising a clamp terminal;  
         [0027]      FIG. 10  is a perspective view of a fixed clamp terminal in a different orientation;  
         [0028]      FIG. 11  is a partial perspective view illustrating a clamp terminal in yet another orientation with a coined fixed terminal;  
         [0029]      FIG. 12  is a partial perspective view of a clamp terminal in a different orientation including lead in edges;  
         [0030]      FIG. 13  is a partial perspective view of a clamp terminal comprising a trifurcated coil clip;  
         [0031]      FIG. 14  is a partial perspective view similar to  FIG. 11  with the clamp terminal in a different orientation;  
         [0032]      FIG. 15  is a partial perspective view of a coil terminal clip as an integral part of a winding coil pin;  
         [0033]      FIG. 16  is a perspective view illustrating a spring loaded fixed terminal;  
         [0034]      FIG. 17  is a partial perspective view illustrating a compression spring coil terminal clip;  
         [0035]      FIG. 18  is an elevation view of the device shown in  FIG. 17 ;  
         [0036]      FIG. 19  is a side view of the device illustrated in  FIG. 17 ;  
         [0037]      FIG. 20  is a partial perspective view illustrating a coil terminal clip in the form of a compression spring;  
         [0038]      FIG. 21  is a plan view of the device of  FIG. 20 ;  
         [0039]      FIG. 22  is a partial perspective view of a fixed terminal comprising a coil spring; and  
         [0040]      FIG. 23  is a plan view of the device of  FIG. 22 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0041]     Referring to  FIG. 1 , an electrical device such as an electromechanical switching apparatus in the form of an electrical contactor  30  is illustrated. In accordance with the invention, the contactor  30  comprises a system and uses a method for connecting a removable coil  32  to a pair of identical fixed coil terminals  34 .  
         [0042]     The contactor  30  is an electromagnetically actuable device and includes a mounting plate  36  for mounting in a control panel or the like. A main housing  38  is mounted to the mounting plate  36 . The main housing  38  includes a base  40  and cover  42 . Referring also to  FIG. 2 , the main housing  38  comprises a cavity  48  receiving the removable electrical coil  32  and an associated electromagnet  44 . The electromagnet  44  includes a magnetic core  46  and conventional armature (not shown). The armature is fixedly mounted in the cavity  48 . The core  46  is inserted in the cavity  48  with the removable coil  32  to provide a functional electromagnet  44 . As is conventional, energization of the coil  32  draws the armature to the magnetic core  46  for driving an actuator having opposite ends  50 . Additionally, the main housing  38  encloses various electrical contacts (not shown) which can be opened or closed by the actuator  50  responsive to energization of the coil  32 , as is conventional.  
         [0043]     The present invention is not limited to the electrical contactor  30  illustrated herein. Instead, the present invention relates to a system and method for connecting the removable coil  32  to fixed coil terminals  34 . This invention may be applied to at least electromechanical contactors, control relays and motor starters, as well as transformers and sensors, which may use removable coils.  
         [0044]     Referring to  FIG. 3 , the coil  32  is illustrated prior to encapsulation. The coil  32  comprises a first bobbin  52  having a first winding  54 . A second bobbin  56  includes a second winding  58 . Opposite ends of the first winding  54  are connected to a start pin  60  and finish pin  62 . Opposite ends of the second winding  58  are connected to a start pin  64  and a finish pin  66 . As will be appreciated, a one piece bobbin could be used for both windings  54  and  58 . The pins are aligned as illustrated in the sequence  60 ,  64 ,  62  and  66 . The first winding start pin  60  is connected, as by soldering or the like, to a coil terminal clip  68 . The second winding finish pin  66  is similarly connected to another coil terminal clip  68 . The coil terminal clips  68  connect to the fixed terminals  34 , as described below, for connecting to an external control voltage source.  
         [0045]     In an exemplary embodiment of the invention, each winding  54  and  58  could be designed to operate at 120 volts AC. If the windings  54  and  58  are connected in series by connecting the second winding start pin  64  to the first winding finish pin  62  a 240 volt AC coil is provided. Alternatively, if the windings  54  and  58  are connected in parallel by connecting the first winding start pin  60  to the second winding start pin  64  and the first winding finish pin  62  to the second winding finish pin  66 , 120 volt AC operation is provided. As is apparent, different voltages could be used, as necessary or desired.  
         [0046]     Although not shown, a slider may be provided for selecting coil voltage by providing the described connections as described in our copending application No. ______ filed concurrently with the present application and assigned to the assignee of the present invention, the specification of which is incorporated by reference herein (Attorney Docket No. 2003P15050US).  
         [0047]     The two coil terminal clips  68  are identical in construction. This reduces the number of different parts. Only one is described in detail herein. Each coil terminal clip  68  comprises a first plate  70  and a second plate  72 . The first plate  70  includes a planar portion  74  turned outwardly to a connecting portion  76  and then turned inwardly to a connecting portion  78 . The second plate  72  similarly includes a planar portion  80  turned outwardly to a connecting portion  82  and then turned inwardly to a connecting portion  84 . The planar portions  74  and  80  are mated with one another. As such, the connecting portions  78  and  84  define a space  86  therebetween which converges moving away from the planar portions  74  and  80  to define a clamp terminal for connecting to the fixed terminals  34 . Each connecting portion  78  and  84  includes an outwardly turned tab  88  and  90 , respectively, to provide a lead in edge  92  to align the coil terminal clip  68  to the fixed terminals  34 . A tab  94  extends from the first piece planar portion  80  for connection to one of the winding pins  60  or  66 , as illustrated.  
         [0048]      FIG. 4  illustrates the coil  32  encapsulated in a plastic housing  96 . The plastic housing  96  is in the form of a rectangular donut shape with the coil terminal clips  68  extending out opposite sides of the housing  96  with the lead in edges  92  opening away from a front wall  98  of the housing  96 , as shown.  
         [0049]     Each of the fixed terminals  34  is identical in construction. More particularly, the fixed terminal  36  is the same on both sides, reducing the number of different parts. Each fixed terminal  34  comprises a formed plate  100  of a conductive material, such as copper. The plate  100  includes a planar portion  102 , connected to a turned portion  104  to a connecting portion  106 . A screw  108  is fastened to the connecting portion  106  for receiving a wire W, see  FIG. 1 , for electrically connecting the coil  32  to an external control circuit. The planar portion  102  includes a through opening  109  for receiving a screw (not shown) for mounting the fixed terminal  34  to the main housing  38 . A projecting portion, defining a blade  110 , extends outwardly on either side of the opening  109 . As described, each fixed terminal  34  can be fixedly mounted to the main housing  38 , as shown in  FIGS. 1 and 2 , with one of the blades  110  from each fixed terminal  34  extending into the cavity  48 . Particularly, the fixed terminals  34  are mounted so that spacing between the opposite blades  110  corresponds to spacing between the lead in edges  92  of the coil terminal clips  68 .  
         [0050]     The removable coil  32  is inserted into the cavity  48  by moving it in the direction of the arrows shown in  FIGS. 2 and 4  with the coil terminal clips  68  aligned with the fixed terminal blades  110 . The lead in edges  92  align the coil terminal clips  68  to the fixed terminals  34  during insertion. When the removable coil  32  is fully inserted, as illustrated in  FIGS. 1 and 5 , the coil terminal clips  68  clamp onto the fixed coil terminal  34  to electrically connect the removable coil  32  to the fixed coil terminals  34  in the housing  38 . More particularly, one of the blades  110  of each fixed coil terminal  34  is clamped in the space  86 . When so inserted, the clamping pressure of the coil terminal clip  68  restrains movement of the removable coil  32  and thus retains the removable coil  32  in the cavity  48 . The sliding cover (not shown), discussed above, can also be moved to lock the coil  32  in the cavity  48 .  
         [0051]     The present invention relates generally to a system and method for connecting a removable coil to a fixed coil terminal in an electrical device.  FIGS. 1-5  illustrate one example of a configuration of a fixed coil terminal  34  and coil terminal clip  68 . Various other embodiments are possible and several are illustrated in the figures and described below. For simplicity and clarity, in the following figures the encapsulated coil is illustrated in partial form and labeled C with a suffix number referencing a particular embodiment. Similarly, only a portion of the fixed coil terminal is illustrated and labeled T with the same suffix number. Also, for simplicity, only one side of the coil is illustrated, it being understood that the removable coil includes two coil terminal clips for mating with two fixed coil terminals.  
         [0052]     Referring initially to  FIG. 6 , a coil C 1  includes coil terminal clips  68  described above for mating with a fixed coil terminal T 1 . Ribs  200  extend from the coil C 2  in front of and behind the coil terminal clip  68 . The ribs  200  protect the coil terminal clip  68  from handling damage. The fixed terminal T 1  is illustrated as a blunt edge blade.  
         [0053]     Referring to  FIG. 7 , a removable coil C 2  includes a formed clamp terminal clip  202  to provide an opening  204  in a plane perpendicular to a main plane of the coil C 2 . The fixed coil terminal T 2  is likewise in a similar perpendicular plane for being received in the opening  204 . The clamp terminal clip  202  is formed of one piece construction and is bifurcated as at  206 .  
         [0054]     Referring to  FIG. 8 , a removable coil C 3  includes a coil terminal clip  208  in the form of a planar leaf spring  210 . A fixed coil terminal T 3  includes a planar portion  212  and is bent downwardly at a distal end  214 . As the removable coil C 3  is inserted, as indicated by the arrow, the coil leaf spring  210  is forced against the fixed terminal distal end  214  along one face only. Although not shown, the leaf spring  210  will bias the removable coil C 3  within the cavity  48  to restrain movement.  
         [0055]     Referring to  FIG. 9 , a removable coil C 4  includes a coil terminal clip in the form of a planar coil contact  216 . A fixed coil terminal T 4  comprises a dual sided clamp terminal  218 . The clamp terminal  218  clamps against side edges  220  of the coil terminal clip  216  when the removable coil C 4  is inserted, as by moving it in the direction of the arrow. This configuration is opposite the initial embodiment where the clamping terminal is mounted to the coil and the fixed terminal comprises a blade.  
         [0056]      FIG. 10  illustrates a removable coil C 5  including a coil terminal clip  222  in the form of a blade and a fixed coil terminal T 5  including a clamp  224  oriented in a plane parallel to the main plane of the coil C 5 , opposite the orientation shown in  FIG. 9 . In this embodiment, the clamping terminal  224  clamps on planar surfaces of the coil terminal clip  222 .  
         [0057]      FIG. 11  illustrates a removable coil C 6  including a coil terminal clip  226  in the form of a clamping terminal formed of two aligned trifurcated plates  28  opening upwardly. Because this design does not include a lead in edge for the coil terminal clip  226 , a fixed coil terminal T 6  includes a coined, sharp edge  230  for aligning with the coil terminal clip  226 .  
         [0058]     Referring to  FIG. 12 , a removable coil C 7  includes a coil terminal clip  232  similar to that shown in  FIG. 11 , without trifurcation, and including a lead in edge  234  for receiving a blunt edge  236  of a fixed coil terminal T 7 .  
         [0059]     Referring to  FIG. 13 , a removable coil C 8  includes a coil terminal clip  238  having a single formed layer  240  protruding from the removable coil C 8  and slotted and bent to define a clamping terminal  242  for receiving a blunt edge fixed coil terminal T 8  in a plane generally parallel to a plane of the coil C 8 .  
         [0060]     Referring to  FIG. 14 , a removable coil C 9  includes a coil terminal clip  244 , generally similar to the coil terminal clip  68 , discussed above, except the coil clip is bifurcated as at  246  with an angled opening  248  directed away from the coil C 9 . This design includes no lead in edge and a coined fixed contact terminal T 9  is utilized.  
         [0061]      FIG. 15  illustrates the removable coil  32 , discussed above, with the coil terminal clip  68 . In this embodiment, the coil terminal clip  68  is integrally formed with the coil winding pin  66  (and likewise on the opposite end, not shown) inside the encapsulation. This eliminates the requirement to solder the coil terminal clip  68  to the winding pin  66  and reduces the number of parts to manufacture the electrical device.  
         [0062]     Referring to  FIG. 16 , an alternative embodiment of the invention is illustrated in the form of a removable coil C 10  including coil terminal clips  250  in the form of a planar blade extending outwardly in a plane transverse to direction of movement of the coil C 10  when inserted. A fixed coil terminal T 10  comprises a housing  252  slidably receiving a conductive terminal  254 . A mounting screw (not shown) is received in a slot  256  of the terminal  254  for holding the terminal  254  while sliding in the housing  252 . A blade  258  extends outwardly from the housing  252  in a path of the coil terminal clip  250 . A coil spring  260  is sandwiched between the housing  252  and the terminal blade  258 . When the removable coil C 10  is inserted, the coil terminal clip  250  makes electrical contact with the fixed terminal blade  258 . The spring  260  provides force for good electrical connection and dampens coil vibrations. The spring  260  can also assist with coil removal. As is apparent, the housing  252  may be an integral portion of the main housing  38 , discussed above. The fixed terminal contact plate  258  includes a contact pad  262  for electrically contacting the coil terminal clip  250 , as is well known.  
         [0063]     Referring to  FIGS. 17-19 , a removable coil C 11  includes a coil terminal clip  264  in the form of a compression spring. The compression spring  264  internally makes contact with the winding (not shown). A fixed coil terminal T 11  comprises a bent terminal. When the coil C 11  is inserted, the compression spring  264  makes contact with the bent edge  266 , as is apparent.  
         [0064]     Referring to  FIGS. 20 and 21 , a removable coil C 12  includes a coil terminal clip  268  in the form of a compression spring  270  which extends rearwardly from a rib  272 . A bobbin  274  holds the spring  270  onto the rib  272 . The spring  270  is wired as indicated in phantom at  276  to the internal winding. When the removable coil C 12  is inserted, in a direction indicated by the arrow, the compression spring  270  is compressed against the fixed surface of the fixed coil terminal T 12 .  
         [0065]     Finally, referring to  FIGS. 22 and 23 , a removable coil C 13  includes a coil terminal clip  278  in the form of a blade contact  280  including a coined edge  282  facing rearwardly. A fixed coil terminal T 13  comprises a plate  284  with a coil terminal screw  286  holding a spring  288  on the plates  284 . When the coil terminal C 13  is inserted, as by moving it in the direction of the arrow, the coined edge  282  is captured in the spring  288 , as is apparent in the plan view of  FIG. 23  so that the fixed terminal T 13  makes electrical contact with the coil terminal clip  278 .  
         [0066]     Thus, in accordance with the invention, various embodiments are illustrated for the general concept of a system and method for connecting a removable coil to a fixed coil terminal. In each embodiment, control wiring is electrically connected to the fixed coil terminals. The removable coil can be removed and replaced without effecting the wiring.