Patent Publication Number: US-6210207-B1

Title: Wire clamp, wire trap electrical connector

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention pertains to an electrical connector. The invention more particularly concerns an electrical connector having features of a wire clamp connector and a wire trap connector. 
     2. Discussion of the Background 
     For years now, competition in the electronics industry has forced contractors to keep material and labor costs at a minimum. Electrical devices and the associated labor required to install the electrical devices are components of the overall cost which must be reduced. The cost of electrical components can most easily be reduced by making them easier to assemble, thus reducing the associated labor cost component of the electrical device. Thus, labor costs are present throughout the assembly of the electrical device and the installation of the electrical device. Other cost are associated with the finished structure such as repair and replacement of electrical devices. 
     To facilitate the installation of printed circuit boards, printed circuit boards are known to have wire clamp or wire trap electrical connectors permanently mounted thereon. The wire clamp and wire trap electrical connectors have one end of their connectors soldered to traces of the printed circuit board, and the other end of their connectors receive external conductors so as to make an electrical connection between the external conductors and the traces on the printed circuit board. 
     The wire trap electrical connector works by pushing a conductor into an entrance of the wire trap electrical connector whereby the electrical connector “traps” the conductor between two opposing electrically conductive members and makes an electrical connection with the conductor. The conductor is press fitted between the two opposing members. Typically, only solid conductors are used in combination with a wire trap electrical connector since the conductor reacts a force along its length during insertion. During such an insertion, a cable made of stranded conductors may flatten out, thus loosing their circular cross-section as an assembly of stranded conductors and, hence, loose the electrical connection with the wire trap electrical connector. 
     Wire trap electrical connectors typically accept, at most, two different gauges of wire. Thus, the environment in which the wire trap electrical connector is assembled to another device must be a controlled environment. Such controlled environments exist at a factory where the housing which contains the wire trap electrical connector is attached to the device. 
     The wire clamp electrical connector works by inserting a conductor into an entrance which is larger than a diameter or thickness of the conductor, thus the conductor slides into the opening with little or no resistance. An external force is then applied to the wire clamp electrical connector so as to “clamp” the conductor between two opposing electrically conductive members of the wire clamp electrical connector thus making an electrical connection between the conductor and the wire clamp electrical connector. The wire clamp electrical connector accepts conductors which are solid as well as stranded conductors. 
     Unlike the wire trap electrical connector, the wire clamp electrical connector accepts many different gauges of conductors, where the conductors can be solid or stranded. Thus, the wire clamp electrical connector can be used in an environment which is not very controlled. Such environments exist out in the field where a device containing the wire clamp electrical connector is connected to pre-existing conductors which the manufacturer of the device has no control over the size and type of conductor which is pre-existing. 
     Wire clamp and wire trap electrical connectors are used since they simplify the attachment of external conductors to printed circuit boards. Furthermore, the attachment of a conductor to a wire trap or a wire clamp electrical connector is repeatable. However, the attachment of wire trap and wire clamp electrical connectors to a printed circuit board are labor intensive, since the connectors are soldered in-place. Such attachment problems are present in the termination of other devices also. One of the most difficult termination applications is the termination of electrical conductors or traces present on devices which are wholly enclosed by a housing. 
     Therefore, there is a need for an electrical connector which is easy to make, easy to install, easy to use, and is inexpensive to produce and can fit in a small space. 
     SUMMARY OF THE INVENTION 
     Therefore, it is an object of the present invention to provide an electrical connector which securely connects to conductors of an enclosed electrical device while providing for reliable, repeatable, connection with conductors external to the housed electrical device. 
     It is still another object of the invention to provide an electrical connector incorporating aspects of a wire trap electrical connector and a wire clamp electrical connector. 
     Yet another object of the invention is to provide an electrical connector having a low profile. 
     It is a further object of the invention to provide an electrical connector which is easy to install. 
     It is still another object of the invention to provide an electrical connector which is easy to assemble. 
     Another object of the invention is to provide an electrical connector which is inexpensive to manufacture. 
     In one form of the invention, the wire clamp, wire trap electrical connector includes a wire clamp electrical connector portion and a wire trap electrical connector portion, where the wire trap electrical connector portion is attached to the wire clamp electrical connector portion. 
     In another form of the invention, the electrical connector includes a wire clamp electrical connector portion and a wire trap electrical connector portion where the wire clamp portion includes a moving arm and a stationary arm where each arm has a respective contact end. An entrance exists between the contact ends. In an open position of the entrance of the wire clamp electrical connector portion, the contact ends are separated by a predetermined gap for receiving a conductor. The gap has a dimension which is greater than a diameter of a conductor. In a closed position of the entrance of the wire clamp electrical connector portion, contact ends are urged toward each other so as to contact and secure the conductor. The wire trap portion includes a moving arm and a stationary arm where the moving arm has a contact end and the stationary arm has a contact surface. An entrance exists between the contact end and the contact surface. In an open position of the entrance of the wire trap electrical connector portion, the contact end and the contact surface are separate by a predetermined gap so as to accept a conductor, where the conductor has a diameter greater than a dimension of the gap. In a closed position of the entrance of the wire trap electrical connector portion, the contact end and the contact surface are separated by a distance greater than the predetermined gap due to the introduction of the conductor into the entrance while the contact end and the contact surface are urged towards each other so as to contact and secure the conductor. 
     In still yet another form of the invention, the wire clamp, wire trap electrical connector includes wire clamping means, and wire trapping means attached to the wire clamping means. 
     Thus, Applicants&#39; invention is superior to existing devices or apparatuses for electrically connecting an external conductor to a conductor or trace of a device or printed circuit board. Applicants&#39; invention provides an electrical connector which is small and inexpensive to produce, while at the same time being easy to manufacture, install, and use. These and other features of the invention are set forth below in the following detailed description of the presently preferred embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
     FIG. 1 is a side view of a wire clamp, wire trap electrical connector; 
     FIG. 2 is a side view of the wire clamp, wire trap electrical connector of FIG. 1 identifying the respective opening of each of the wire clamp electrical connector portion and the wire trap electrical connector portion; 
     FIG. 3 is a side view of the wire clamp, wire trap electrical connector of FIG. 1 where conductors are introduced therein; 
     FIG. 4 is a side view of the wire clamp, wire trap electrical connector and conductors of FIG. 3 where the conductors are fully engaged therein; 
     FIG. 5 is a side view of the wire clamp, wire trap electrical connector of FIG. 1 where a housing  70  substantially surrounds the wire clamp, wire trap electrical connector, wherein the housing has an activation lever for actuating the wire clamp electrical connector portion; 
     FIG. 6 is a perspective view of a housing and an electrical device joined with the housing where the housing secures a wire clamp, wire trap electrical connector; 
     FIG. 7 is a side view of the housing and electrical device of FIG. 6 where internal features are shown in phantom line; and 
     FIG. 8 is a side view of another embodiment of the wire clamp, wire trap electrical connector shown in phantom line. 
    
    
     DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS 
     Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, and more particularly to FIGS. 1-4 thereof, a first embodiment of the present invention is a wire clamp, wire trap electrical connector  10 . 
     FIG. 1 is a side view of the wire clamp, wire trap electrical connector  10 . The wire clamp, wire trap electrical connector  10  includes a wire clamp electrical connector portion  20  and a wire trap electrical connector portion  30 . 
     The wire clamp electrical connector portion  20  includes a moving arm  22  and a stationary arm  26 . The moving arm  22  has a contact end  24  and the stationary arm  26  has a contact end  28 . The contact end  24  of the moving arm  22  is separated from the contact end  28  of the stationary arm  26  by a gap or entrance  29 . 
     The wire trap electrical connector portion  30  includes a moving arm  32  and a stationary arm  36 . The moving arm  32  has a contact end  34  and the stationary arm  36  has a contact surface  38 . The contact end  34  of the moving arm  32  is separated from the contact surface  38  of the stationary arm  36  by a gap or entrance  39 . 
     In a preferred embodiment, the wire clamp, wire trap electrical connector  10  is formed from a single piece of metal. The wire trap electrical connector portion  20  being electrically connected to the wire clamp electrical connector portion  30  via ribs (not shown) which project into the plane of FIG.  1 . Various bends  12 ,  14 ,  16 ,  18  illustrate the bending of the metallic material. The metallic material, once formed, has elastic material properties so as to allow the moving arms  22 ,  32  to deflect without experiencing permanent deformation. Additionally, the metallic material needs to have an acceptable fatigue life so as to enable the moving arms  22 ,  32  to deflect numerous times without breaking. Furthermore, the metallic material needs to have acceptable electrical conductivity characteristics. 
     The wire clamp, wire trap electrical connector  10  can also be constructed of other materials such as metallized plastic. The molded polymer body of such a material provides the needed elasticity, while the metallized outer coating provides the needed electrical conductivity. 
     FIG. 2 is a side view of the wire clamp, wire trap electrical connector  10 , as in FIG. 1, which identifies a size dimension WC of the entrance  29  of the wire clamp electrical connector portion  20  and a size dimension WT of the entrance  39  of the wire trap electrical connector portion  30 . FIG. 2 shows both the wire clamp electrical connector portion  20  and the wire trap electrical connector portion  30  in an open position. 
     FIG. 3 is a side view of the wire clamp, wire trap electrical connector  10 , as in FIG. 1, in combination with cables  40 ,  50 . Cable  40  includes a conductor  42  and an insulative layer  44  covering a majority of the conductor&#39;s surface. Conductor  42  is typically a solid conductor. Conductor  42  has a size, diameter, thickness or width dimension identified as C 1 . Cable  50  includes a conductor  52  and an insulative layer  54  covering a majority of the conductor&#39;s surface. Conductor  52  can be a solid conductor or a stranded conductor. Conductor  52  has a size, diameter, thickness or width dimension identified as C 2 . 
     The size dimension C 2  of conductor  52  is smaller than the size dimension WC of the entrance  29  of the wire clamp electrical connector portion  20 . The size dimension C 1  of the conductor  42  is larger than the size dimension WT of the entrance  39  of the wire trap electrical connector portion  30 . 
     FIG. 4 is a side view of the wire clamp, wire trap electrical connector  10  and conductors  42 ,  52  of FIG. 3, where the conductor  42  is fully engaged in the wire trap electrical connector portion  30  and the conductor  52  is fully engaged in the wire clamp electrical connector portion  20 . FIG. 4 shows both the wire clamp electrical connector portion  20  and the wire trap electrical connector portion  30  in a closed position. 
     Conductor  52  is introduced into the wire clamp, wire trap electrical connector  10  at approximately ninety degrees to the introduction of conductor  42  into the wire clamp, wire trap electrical connector  10 . Both conductors  42 ,  52  are introduced into the wire clamp, wire trap electrical connector  10  in a direction which parallels their respective longitudinal axes or directions. However, in other embodiments, the entrances of both the wire clamp electrical connector portion  20  and the wire trap electrical connector  30  can be oriented relative to each other at angles other than ninety degrees. 
     Since the width dimension C 1  of conductor  42  is greater than the gap dimension WT of the entrance  39 , the conductor  42  causes the moving arm  32  of the wire trap electrical connector portion  30  to elastically move in a direction away from the stationary arm  36  as the conductor  42  is introduced therein. Furthermore, the conductor  42  is easily introduced into the entrance  39  since the moving arm  32  and the stationary arm  36  form a vertex or funnel type of shape. Once fully inserted into the wire trap electrical connector portion  30 , the conductor  42  is trapped between the contact end  34  of the moving arm  32  and the contact surface  38  of the stationary arm  36 . Since the moving arm  32  is deflected, it applies a force to the conductor  42  and urges the conductor  42  toward the stationary arm  36 . Thus, the wire trap electrical connector portion  30  is in electrical contact with the conductor  42  via either one or both of the contact end  34  and the contact surface  38 . 
     To detach conductor  42  from the wire trap electrical connector portion  30 , a tool (not shown) can be pressed against the moving arm  32  so as lift the contact end  34  off of the surface of the conductor  42  thus forming a disengagement gap which is larger than the thickness of the conductor  42 . Then, the conductor  42  can be pulled out of the entrance  39 . To prevent the moving arm  32  from being deflected too far, and hence be overstressed, when the tool is pressed against it, a housing in which the wire trap electrical connector portion  30  is housed can have features which prevent the moving arm  32  from deflecting too far. Such an anti-overstress features are disclosed in U.S. patent application Ser. No. 09/224,611. U.S. patent application Ser. No. 09/224,611 is hereby incorporated herein by reference. 
     Since the width dimension C 2  is less than the gap dimension WC of the entrance  29  of the wire clamp electrical connector portion  20 , an external force F 1  must be applied to the moving arm  22  and reacted out of the stationary arm  26  so as to clamp the conductor  52  between the contact end  24  of the moving arm  22  and the contact end  28  of the stationary arm  26 . The external force F 1  can be applied by hand, machine, gravity, electromagnetism, fluid pressure, etc. The external force F 1  ensures that electrical contact is achieved between the conductor  52  and either one or both of the contact end  24  of the moving arm  22  and the contact end  28  of the stationary arm  26 . Thus, conductor  52  is in electrical contact with conductor  42  via the wire clamp, wire trap electrical connector  10 . 
     To detach conductor  52  from the wire clamp electrical connector portion  20 , the external force F 1  must be removed. Upon removal of the external force F 1 , the moving arm  22  returns to its undeflected or free state position due to its elasticity. Conductor  52  can then be pulled out of the entrance  29 . 
     The stationary arms  26 ,  36  remain stationary since they are constrained from moving. The stationary arms  26 ,  36  are constrained from moving since the wire clamp, wire trap electrical connector  10  is, typically, housed in an insulative shell, body, or housing. 
     FIG. 5 is a side view of the wire clamp, wire trap electrical connector  10  positioned within a housing  70 . Only the wire clamp electrical connector portion  20  is visible. The housing  70  includes an activation lever  60  pivotally mounted thereto. The lever  60  includes a cammed surface  62 . The cammed surface  62  slides against a surface of the moving arm  22 . In use conductor  52  is introduced into the entrance  29  of the wire clamp electrical connector portion  20 , then the activation lever  60  is rotated so that the cammed surface  62  pushes a portion of the moving arm  22  toward the stationary arm  26  so as to clamp the conductor  52  between the contact ends  24 ,  28 . To release the conductor  52 , the activation lever  60  is rotated in an opposite direction which removes the cam action of the cammed surface  62  from the surface of the moving arm  22 . Then, the moving arm  22  returns to its free state position since it is not being acted upon by an external force. 
     FIG. 6 is a perspective view of a housing  700  joined with an electrical device  800 . The housing  700  secures a wire clamp, wire trap electrical connector (not shown) therein. In such an embodiment, the wire trap electrical connector portion accepts an internal conductor positioned within the electrical device. The environment in which the wire trap electrical connector portion connects to the internal conductor is controlled. The internal conductor has a known gauge size. The wire trap electrical connector portion traps the internal conductor in a factory floor environment. Then, the wire trap electrical portion is used to connect with an external conductor. The external conductor is out in the field, a field installation. The manufacturer of the combined housing  700  and device  800  has no control over the type and gauge size of the external conductor. This embodiment is well suited to the invention, since the wire trap electrical connector portion can be blindly and permanently connected to the internal conductor, while the wire clamp electrical connector portion can be repeatedly clamped on and off of the external connector. 
     In the past, a device similar to device  800  would have two insulated conductors extending out of the housing of the device. In the field, the laborer would strip the insulation off of the conductors of the device and also strip insulation off of the conductors to which the conductors of the device are to be connected. The laborer would then join the appropriate conductors by spinning a wire nut on the exposed conductors. Now, with the use of the wire clamp, wire trap electrical connector, the laborer merely strips the insulation away from the field conductors, inserts the field conductors into the wire clamp electrical connector portion of the wire clamp, wire trap electrical connector, and rotates the lever to lock the field conductors in-place. 
     FIG. 7 is a side view of the housing  700  and the electrical device  800  of FIG.  6 . Internal features of an embodiment of the wire clamp, wire trap electrical connector  100  are shown in phantom line. Note that the vertex or funnel of the wire trap electrical connector portion is oriented differently than the way it is positioned in FIG. 1 relative to the wire clamp electrical connector portion. Furthermore, also as different from FIG. 1, the stationary arm  26   a  of the wire clamp electrical connector portion extends farther away from the wire trap electrical connector portion than does the moving arm  22   a.    
     FIG. 8 is a side view of another embodiment of the wire clamp, wire trap electrical connector  100   a  positioned in a housing  700   a , which is similar to the connector  10  displayed in FIG.  5 . However, in this embodiment the stationary arm  26   b  extends farther from the wire trap electrical connector portion  300   a  than does the moving arm  22   b . The housing  700   a  includes an activation lever  600   a  which has a cammed surface. The wire clamp electrical connector portion  200   a  and the wire trap electrical connector portion  300   a  of the wire clamp, wire electrical connector  100   a  are clearly shown in phantom line. 
     In another embodiment, the stationary arms  26 ,  36  can move and the moving arms  22 ,  32  can be stationary. In still another variation of the invention, all of the stationary arms  26 ,  36  and the moving arms  22 ,  32  can move. 
     In still another embodiment, the wire clamp, wire trap electrical connector can include one wire clamp electrical connector portion attached to two wire trap electrical connector portions. 
     In still yet another embodiment, the wire clamp, wire trap electrical connector can include one wire trap electrical connector portion attached to two wire clamp electrical connector portions. 
     Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.