Abstract:
Electrical wiring devices and methods of connecting leads to wiring devices are disclosed comprising terminal blades, cage clamps, insulating housings and hand-operable actuators for engaging and disengaging the cage clamps, wherein the actuators are integral to the wiring devices. The connection of leads to wiring devices using cage clamps and integral, hand-operable actuators produces improved safety, durability and performance of the wiring devices.

Description:
RELATED APPLICATIONS  
       [0001]     This application claims priority to U.S. Provisional Application Ser. No. ______ entitled “ELECTRICAL WIRING DEVICE” filed Oct. 28, 2003 on behalf of Robert R. Luther and Arnold R. Tang. The entire disclosure of that application is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The invention described herein relates generally to the field of wiring devices and specifically to the field of wiring devices incorporating cage clamps.  
         [0004]     2. Description of the Related Art  
         [0005]     Wiring Devices are a well-defined product category of electrical connectors utilizing straight or curved blades for male contacts and complimentary resilient blades for female contacts. Harvey Hubbell invented the first wiring device in 1897. The contacts of modem wiring devices are arranged in configuration patterns that ensure non-interchangeability for varying voltage ratings and their capacities range from 10 amps at 120 volts to 60 amps at 600 volts. The National Electrical Manufacturers Association (hereinafter “NEMA”) defines the configuration patterns for many wiring devices. The products falling within this family of wiring devices are known as NEMA wiring devices.  
         [0006]      FIG. 1   a  is an exploded view of a typical existing male wiring device  100 . The wiring device  100  is used to provide a standard termination for a wire lead  10 . The wire lead  10  passes through a passage  15  in a closed end of a generally tubular insulating backshell  120  and is secured within an insulating insert  108  where it is connected to one or more terminal blades  105 ,  106 . The insulating insert  108  that is illustrated includes a somewhat cylindrical body that mates with and fits within the insulating backshell  120  to hold and insulate the terminal blades  105 ,  106 . The blades  105 ,  106  are typically metallic and are flat and rectangular in shape, although some existing blades  105 ,  106  commonly used are curved or shaped into pin-type blades. The blades  105 ,  106  are mounted in and supported by the insulating insert  108 , which can also serve to provide, in part, a location for a user to hold the wiring device  100  without touching the blades  105 ,  106 . The illustrated wiring device  100  also includes a pin-type blade for a grounding pin  106 . The illustrated grounding pin  106  has been formed into a round pin.  FIG. 1   b  is an end view of the wiring device  100  of  FIG. 1   a  illustrating the circular cross-section of the wiring device  100  along with the terminal blades  105  and the grounding pin  106 .  
         [0007]     Traditional wire termination methods use exposed screws to provide the necessary physical force to effect physical and electrical connection between a wire, or a set of wires, and a wiring device.  FIG. 1   c  is a cutaway exploded side view of the male wiring device  100  of  FIG. 1   b  taken along line  1 - 1 , and illustrates two existing connection designs utilizing screws for connecting the lead  10  to the terminal blades  105 .  FIG. 1   d  is a cutaway side view of a female wiring device  102 , taken along a similar line in that device as  FIG. 1   c,  that is adapted to mate with the wiring device  100  of  FIG. 1   c.  The female wiring device  102  has female blades  107  that are made in a similar manner as the male wiring device blades  105  and are shaped to resiliently mate with the terminal blades  105  of the male wiring device  100 . A female insulating insert  115   a  supports the female blades  107  and provides a housing to accept the male blades  105  and house the connection between the male and female blades  105 ,  107 . Common wiring devices  100  can also include a termination insulator  118  for housing and insulating the connection between the terminal blades  105  and the lead  10 . The termination insulator  118  can be many shapes, depending upon the termination scheme utilized, but generally consists of a hollow geometric shape attached to the insulating insert  115  or a separate internal insulator  116 . The internal insulator  116  is used in some wiring devices  100  for additional electrical and thermal insulation and consists of a disk of insulative material that abuts the insulating insert  115  and has passages for the terminal blades  105  and grounding pin  106 .  
         [0008]     Referring to  FIG. 1   c,  the illustrated wiring device  100  includes two existing termination structures. One termination structure is enclosed in a termination insulator  118  and the other is not. The first, exposed termination scheme is a common and simple “binding screw terminal”  122  that consists simply of a threaded screw  126  that screws into the terminal end of the terminal blade  105 . Typically, wire from the lead  10  is wrapped around the binding screw  126  and the screw  126  is tightened to physically secure and electrically connect the wire to the terminal blade  105 . The compression force of the binding screw  126  is limited because the forces it presents to a connected wire are not just compressive, but also frictional, as the screw is rotated. Such termination structures are subject to failure as the binding screw loosens from vibration and electro-thermal expansion and contraction of the terminal blade  105 , screw  126 , and wire.  
         [0009]     The construction of wiring devices has advanced over the years to embody a screw drawing two clamps together upon the conductor to make the electrical connection. Still referring to  FIG. 1   c,  an existing improvement to the binding screw  126  is illustrated as the compression terminal  124 . A compression terminal  124  is similar to a binding screw  126 , in that a screw  127  is inserted through the terminal blade  105 . However, a compression plate  128  is added to compress the wire between the compression plate  128  and the terminal blade  105 . The compression plate  128  is a flat piece of threaded metal that is drawn toward the terminal blade  105  as the screw  127  is tightened, thereby clamping the wire to the terminal blade  105 . This arrangement allows the terminated wire to be clamped with greater compression than is possible with binding screw terminals  122 , reducing or delaying loosening effects caused by vibration and by electro-thermal expansion and contraction.  
         [0010]     Referring to  FIGS. 1   a  and  1   c,  the insulating backshell  110  is assembled onto the back of the wiring device  100 , after the terminations are complete, to house the termination and, as mentioned before, to allow a location for a user to hold, connect, and disconnect the wiring device  100  without touching electrified components. Many wiring devices  100  include a cable clamp  130 . The cable clamp  130  is an opening in the insulating backshell  120  through which a lead penetrates. Once assembled, the cable clamp  130  is engaged, and mechanically secures the lead  10  to the completed wiring device  100  so as to prevent damage to the individual wires and terminations within.  
         [0011]     These screw-type terminations are common in the field of electrical devices, however, the screw methods for such connections have several drawbacks. The first problem is creep. The fine strands of a stranded copper conductor can have a tendency to shift and further compress, even when the screw is tightened with the proper amount of torque. This shifting may result in a reduction of clamping pressure applied to the conductor, leading to a rise in heat generated from the connection. Heating and cooling of the conductors may result in further shifting of the conductors, and ultimately device failure.  
         [0012]     Vibration is another action that can reduce the effectiveness of screw terminals. Vibration from motors or other machinery, or transport of the wiring device can cause screws to loosen leading ultimately to device failure. Furthermore, such terminations can be negatively affected by insufficient initial torque. It is up to the installer to apply the proper amount of torque to screws to make a proper electrical connection. It is rare for an installer to use a torque screwdriver, so resultant insufficient torque is not uncommon. Insufficient torque will result in inadequate contact pressure applied to the conductor, again leading to a rise in heat from the connection and eventual device failure. Applying too much torque to a terminal screw, or “overtorquing,” can cause problems as well. Overtorquing the terminal screw can result in stripping the terminal screw as well as physical damage to the lead. A stripped terminal screw will provide inadequate pressure on the conductor resulting in a rise in heat generated be the connection and ultimately device failure.  
         [0013]     Furthermore, screws require a screwdriver for assembly, which can be a source of injury to personnel and can be inconvenient in complicated installations. Additionally, in situations where the insulating shell of the wiring device accidentally comes loose, the screws can be exposed to the operator and contacted and thereby present an electric shock hazard to users of these wiring devices.  
         [0014]     Alternative connection mechanisms to screws include the “spring clamp” and “cage clamp.” These items usually constitute a bent piece of banded metal that “creates” a resilient spring action that provides the required force for physical and electrical connection.  FIGS. 2   a,    2   b  and  2   c  illustrate wiring devices  200  utilizing existing “spring clamp” or “cage clamp” terminations for connectors and wiring devices. The cage or spring clamps utilized currently are not applied to NEMA wiring devices due to the size of the conductors that are involved in such devices, but rather, are applied to small circuitry for electronic equipment.  FIGS. 2   a,    2   b  and  2   c  only illustrate the termination of one of the terminal blades  205  and the associated components for that termination for simplicity only. The terminations of the other terminal blades that are not shown in these figures are made in the same way with similar components for the other lead wires and terminal blades  105 . As illustrated in  FIGS. 2   a,    2   b  and  2   c,  a cage clamp is employed by locating a specially shaped spring  210  within the termination insulator  218 . The spring  210 , as illustrated in the detail, is a flat band of metal that is folded into a resilient shape with an opening for passage of a lead. The spring  210  is typically metallic and is fashioned by stamping, machining, and other metalworking processes. During its manufacture, a hole  215  or channel is typically fashioned into the spring  210 , as shown in the detail view. In its normal (disengaged) state, the spring retains a shape such that the hole is located mostly adjacent the terminal blade  205  and so that a wire to be terminated cannot be inserted into the hole  215  until the spring  210  is activated.  
         [0015]     An operating opening  220  is formed in the termination insulator  218  and allows a user top apply an operating force to a portion of the spring  210 , thereby compressing it into an “engaged” state, whereby the exposed portion of the hole  215  in the spring  210  is enlarged enough for an electrical conductor to pass through. Termination of a wire in a “cage clamp” is effected by placing physical force upon the spring  210  to place it into its “engaged” state, inserting a wire in the hole  215 , and then removing the engaging force. The spring  210  returns toward its disengaged state, causing the side of the hole  215  to bear force upon the wire, effecting a mechanical and electrical connection to the terminal end of the terminal blade  205 .  
         [0016]      FIGS. 2   b  and  2   c  illustrate a typical cage clamp termination utilized in electronic circuitry. The engaging force “F” is applied to the spring by forcing a pointed tool or object into the operating opening  220  to engage the spring  210 . The hole  215  in the spring  210  is sufficiently exposed to allow a wire or conductor  225  to pass through. Upon the removal of the engaging force F, the wire or conductor  225  is trapped in the hole  215  and thereby terminated against the terminal end of the terminal blade  205 .  
         [0017]     The side of the hole  215  in the spring  210  provides a constant force upon the terminated conductor  225  under a variety of circumstances, which can present reliability problems for termination methods utilizing screws. Screws can become loosened under vibration, whereas the spring  210  will not loosen. The terminal  205  and wire  225  expand and contract as they heat up and cool as the electrical load through them varies, which can cause termination methods using screws to work loose. In contrast, a spring  210  will maintain the same force despite this electro-thermal expansion and contraction.  
         [0018]     One disadvantage of the “cage clamp” design is that in many embodiments the engaging force F is not mechanically limited. Excessive engaging force F can cause permanent damage to the spring  210 . Existing “spring clamp” and “cage clamp” designs as shown in  FIGS. 2   a,    2   b  and  2   c  also present a risk of electrical shock should the connector/wiring device&#39;s  200  insulating backshell (not shown in these figures) become loose or detached, because the spring  210  is exposed through the operating opening  220 . Some embodiments, as represented in  FIG. 2   a,  reduce the size of the operating opening  220  to reduce, but not totally eliminate, the risk of electric shock. This increases the need to utilize a sharp or pointed tool such as a screwdriver, thereby reducing convenience and increasing assembly time and complexity.  
         [0019]     Therefore, there is a need for an improved wiring device that does not require a tool such as a screwdriver to operate, that provides a reliable electrical and mechanical connection and that provides an amount of protection from electrical shock to the user while connections are being made between the device and a lead. There is an additional need for a wiring device that utilizes a termination mechanism that consistently applies the correct amount of clamping force to a conductive lead. There are additional needs in the field of wiring devices that are met by the embodiments described herein that will become apparent to those of skill in the art upon reviewing the description of the various embodiments described herein.  
       SUMMARY OF EMBODIMENTS OF THE INVENTION  
       [0020]     An electrical wiring device is described in one embodiment, comprising a conductive terminal, a resilient cage clamp having a terminal opening adapted to accept the passage therethrough of a portion of the terminal, the cage clamp also having an actuation surface adapted to enlarge the terminal opening when the actuation surface is depressed, a cage clamp actuator located in close proximity to the actuation surface so as to depress said actuation surface when the cage clamp actuator is operated, and an insulating housing partially enclosing the terminal and the cage clamp and configured to retain at least a portion of the actuator. In this embodiment, the actuator is adapted for hand-operation in order to depress said actuation surface. Some embodiments conform to NEMA design standards.  
         [0021]     Some embodiments of the electrical wiring device further comprise an insulating cover adapted to mate with the housing and to encapsulate the cage clamp, the actuator and to partially enclose the terminal.  
         [0022]     In other embodiments of the electrical wiring device, the actuator further comprises a rotatable cam adapted to rotate between at least a first cam position and a second cam position, wherein when the cam is in the first cam position, the actuation surface is fully released and wherein when the cam is in the second cam position, the actuation surface is fully depressed, and a cam lever attached to the cam and adapted to rotate the cam into the first and second cam positions.  
         [0023]     In yet another embodiment, an electrical wiring device is disclosed comprising; a blade-type wiring terminal, a cage clamp in contact with the terminal, wherein the cage clamp is adapted to receive and retain an electrical lead when actuated, and wherein the cage clamp is further adapted to electrically and mechanically couple the wiring terminal with the electrical lead, and the electrical wiring device further comprises an integral hand-operated actuator in proximity to the clamp and adapted to actuate the cage clamp.  
         [0024]     In still another embodiment, a method of manufacturing a wiring device is disclosed, comprising molding a blade-shaped terminal, forming a, opening in a middle section of a flat resilient conductor, forming the conductor generally into a loop with the opening along a middle portion of the loop, extending the terminal partially through the opening, forming a nonconductive actuator with a handle adapted to displace a portion of the conductor, wherein the actuator is formed such that it is capable of being operated by hand, and the method further comprising housing the conductor, the terminal and the actuator in an insulative body in a manner such that the terminal is generally parallel with the plane of the loop while extending partially within the opening and such that the actuator is in operable proximity with at least a portion of the resilient conductor. In some embodiments, the body houses the conductor, the terminal and the actuator in a manner such that the resilient conductor rests at a state where the majority of the opening is misaligned with the terminal, and the resilient conductor can be displaced from its rest position to a position such that the opening is aligned with the terminal to form an opening into which a conductive lead may be inserted, such that when the resilient member is returned to its rest position, it impinges the inserted lead against the terminal. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]      FIG. 1   a  is an exploded perspective view of an existing wiring device.  
         [0026]      FIG. 1   b  is an end view of the wiring device of  FIG. 1   a.    
         [0027]      FIG. 1   c  is a partial cutaway side view of the wiring device of  FIG. 1   b  taken along line  1 - 1  and illustrating two existing termination schemes.  
         [0028]      FIG. 1   d  is a partial cutaway side view of a female wiring device complimentary to the male wiring device of  FIG. 1   c,  taken from a corresponding female wiring device along a line analogous to line  1 - 1  of  FIG. 1   b.    
         [0029]      FIGS. 2   a  and  2   b  are partial cutaway side views of wiring devices similar to that illustrated in  FIG. 1   b  taken along line  1 - 1  and illustrating existing termination schemes utilizing a cage clamp for small electronics applications.  
         [0030]      FIG. 2   c  is a partial cutaway side view of the wiring device illustrated in  FIG. 2   b  and illustrating the retention of a lead by the cage clamp.  
         [0031]      FIG. 3   a  is a partial cutaway side view of the wiring device of  FIG. 1   b  taken along line  1 - 1  and illustrating an operating lever for activating a cage clamp.  
         [0032]      FIG. 3   b  is a partial cutaway side view of the wiring device of  FIG. 3   a  illustrating an operating force applied to the operating lever of the device of  FIG. 3   a  to engage the cage clamp.  
         [0033]      FIGS. 4, 4   a  and  4   b  are partial cutaway side views of an alternative wiring device utilizing an actuating pin as an integrated actuator.  
         [0034]      FIGS. 5, 5   a,    5   b  and  5   c  are partial cutaway side views of an alternative wiring device utilizing an actuating lever and “cam”.  
         [0035]      FIGS. 6 and 6   a  are partial cutaway side views of another alternative wiring device utilizing an actuating lever, a cam and a push “rod”.  
         [0036]      FIG. 7  is a perspective and partial cutaway view of the assembled embodiment of the wiring device of  FIGS. 5, 5   a,    5   b  and  5   c.    
         [0037]      FIG. 8   a  is a partial cutaway side view of an alternative to the embodiment illustrated in  FIG. 7 .  
         [0038]      FIG. 8   b  is a perspective and partial cutaway view of the wiring device of  FIG. 8   a.   
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0039]     Embodiments of the invention will now be described with reference to the accompanying figures, wherein like numerals refer to like elements throughout. The terminology used in the description presented herein is not intended to be interpreted in any limited or restrictive manner simply because it is being utilized in conjunction with a detailed description of certain specific embodiments of the invention. Furthermore, embodiments of the invention may include several novel features, no single one of which is solely responsible for its desirable attributes or which is essential to practicing the inventions herein described. The figures and descriptions in the balance of this application describe male connectors and wiring devices, although the inventions disclosed are equally applicable to female connectors and wiring devices. Many figures in the balance of this application also illustrate the termination of a single terminal or a single conductor, although the inventions disclosed are applicable to connectors and wiring devices with any quantity of terminals or conductors.  
         [0040]      FIGS. 3   a  and  3   b  illustrate a wiring device  300  utilizing an integral actuator for activating, holding and releasing a cage clamp  310  by hand, without the need of a tool. The actuator of this embodiment is an operating lever  330  for activating a cage clamp  310 . The embodiment illustrated includes common components described above, such as, one or more terminal blades  305 , an insulating insert  315 , an internal insulator  316 , a termination insulator  318  and an insulating backshell  320 . Many of these components can be combined, such as the insulating insert  315  and the internal insulator  316  or the termination insulator  318 , as design conditions for a particular embodiment may allow. However, this embodiment also includes an insulating operating lever  330  with a hinge  335 , which cooperate to insulate the user from the cage clamp  310  while also allowing activation of the cage clamp  310  by hand and without the need for tools.  
         [0041]     As illustrated in  FIG. 3   a,  embodiments of the wiring device  300  include an elongated operating lever  330  for actuation of the cage clamp  310 . The operating lever  330  can be any elongated piece of rigid material mounted generally at or near one end via a pin joint to form the hinge  335  such that the rest of the operating lever  330  can rotate about the hinge  335 . The operating lever  330  is further shaped with an operating pin  340  generally opposite the hinge  335 . The operating pin  340  is a lateral extension protruding generally perpendicularly from the axis of the elongated operating lever  330  that transmits an engaging force to an appropriate point upon the cage clamp  310 . The operating pin  340  can be made of any material that is either conducting or non-conducting, and can be fashioned as a separate component or formed as part of the operating lever  330 . The operating pin  340  is positioned and shaped so as to provide a mechanical advantage or disadvantage, amplifying or attenuating the engaging force applied to the operating lever  330 .  
         [0042]     For instance, for easier operation, the operating pin  340  is situated such that it contacts the cage clamp  310  at a point far from the dynamic bend  312  of the horizontal side of the cage clamp  310  that mates with the terminal blade  305 . The dynamic bend  312  of the cage clamp  310  is the bend/part that most elastically deforms during activation and deactivation of the cage clamp  310 . By contacting the cage clamp  310  at a point far from this dynamic bend  312 , the cage clamp  310  is easier to activate while making a termination. By forming the operating pin  340  and lever  330  in a manner such that the operating pin  340  applies force to the cage clamp  310  at a location near the dynamic bend, the cage clamp  310  becomes more difficult to operate. Embodiments incorporating such design features allow manufacturers to create wiring devices that are advantageous for the particular size of connectors that are to be connected to the wiring device  300 . For instance, if a smaller thickness conductor is to be connected to the wiring device  300 , some embodiments employ an operating lever  330  and pin  340  combination that is more difficult to operate. In such a design, a user observes the size of the conductor and the size of the wiring device  300  and contemplates a range of force that he/she expects to be required for activation of the cage clamp  300 . When the actuator design provides resistance to the activation force near the maximum of that contemplated range, it is unlikely that an operator would apply significantly more than he/she expects to be the top of that range. Therefore, fewer instances of over-compressing the cage clamp are expected to occur, leading to even greater reductions of the number of failures in such devices.  
         [0043]     The operating lever  330  of the embodiments illustrated in  FIGS. 3   a  and  3   b  also includes a mechanical stop  345 , which is an extended area of the rotating end of the lever  330 . The mechanical stop  345  limits the travel of the lever  330  during compression of the cage clamp  310  by contacting the termination insulator  318  at a stop point  348  shaped and located to cooperate with the mechanical stop  340  of the lever  330 . In some embodiments, the range of rotation of the lever  330  is limited in the other direction by a back stop  349 . The back stop  349  is an area of the opening in the termination insulator  318  that serves as a stopping point for the rotation of the lever  330  when the cage clamp  310  is being released. In other words, the range of rotation of the lever  330  and thus the operating pin  340  is limited by the size of the opening in the termination insulator  318 . Alternatively, on embodiments not utilizing a termination insulator  318 , the stop point  348  and the back stop  349  can be any other structure capable of limiting the rotation of the lever  330  in the forward or reverse directions. For instance, the stop point  348  and the back stop  349  can be two or more struts extending from one area inside the insulating insert  315 , internal insulator  316  or the insulating backshell or any other component. Additionally, the operating lever  330  may include its own rotation range limiting extensions (not shown) extending from anywhere along the length of the lever  330  out and away from the longitudinal axis of the lever  330  in a straight or curved path. As such extensions stretch out from the lever  330 , they hinder the lever  330  from rotating more than the design travel.  
         [0044]     In many embodiments, the operating lever  330 , the hinge  335 , the operating pin  340  and the termination insulator  318  are cooperatively shaped such that electrically energized portions of the cage clamp  310  and terminal blade  305  are minimally exposed. In many embodiments, physical contact with electrically conductive components can only be made by extreme or deliberate acts by a user, even when the insulating backshell  320  is accidentally or deliberately removed.  
         [0045]     When the operating lever  330  is operated to either extreme of travel, an optional tactile feedback “click” is transmitted to a person operating the lever thereby letting them know that such a limit has been reached. Such a tactile feedback can be created by a variety of means including matching protrusions molded into the lever  330  and the termination insulator  318 , the stop point  348  or the back stop  349  that closely mate to provide the desired feedback. In some embodiments, this feedback mechanism can also hold the lever  330  in the position that engages the cage clamp  310 , allowing a conductor (not shown) to be inserted into the cage clamp  310  without requiring continuous engagement force.  
         [0046]     The operating lever  330  of some embodiments is shaped such that when the insulating backshell  320  is installed, the entire lever  330  remains clear of the inside surface of the insulating backshell  320 . A line  350  illustrates the path of the internal surface of the insulating backshell  320  and shows how the lever  330  remains clear and does not contact the backshell  320  at any point. Such a configuration prevents accidental operation of the lever  330  while the wiring device is fully assembled.  
         [0047]      FIG. 3   b  illustrates the embodiment of  FIG. 3   a  in the activated or engaged position. In this illustrated embodiment, an activating force F is applied by simple, manual finger pressure. The operating pin  340  contacts the cage clamp  310  at a contact point  355  thereby compressing the cage clamp  310  and positioning the cage clamp hole (not shown) below the terminal blade  305  and allowing a wire to be inserted into the hole. The lever  330  and the termination insulator  318  of certain embodiments are specially shaped such that they contact at stop point  348 , thereby preventing excessive compression of the spring, and thereby preventing plastic deformation of the spring. The cage clamp  310  is engaged by the operating pin  340  in such a manner as to provide an opening for connecting a wire or lead to pass through the hole and into the cage clamp  310  adjacent the terminal blade  305 . Once the wire is inserted, the lever  330  is released into its original or disengaged position, where it is held in this position by the cage clamp  310 .  
         [0048]     Referring to  FIGS. 3   a  and  3   b,  the operating lever  330  may be made of any material that can be formed into a shape capable of operating the cage clamp  310  and capable of applying the amount of force required to activate the cage clamp  310 . The embodiment illustrated can be designed for a variety current ratings. Many embodiments are designed to accept leads capable of reliably conducting up to 10 amps, 20 amps, 30 amps, 40 amps, 50 amps and more. In embodiments capable of higher current conductance, a stronger cage clamp  310  is utilized to provide the resilient force necessary to make and hold a reliable electrical connection. Accordingly, the operating lever  330  of these embodiments is constructed of a design and material capable of supplying the appropriate amount of force. For example, in embodiments where the cage clamp  310  is designed to provide a high amount of clamping force to the lead when an electrical connection is made, the operating pin  340  is more robust to provide more force and a material is selected to support the additional force. Many embodiments utilize materials that are electrically insulative and thermally stable. For example, many embodiments utilize thermoplastic or thermoset materials, such as polyvinyl chloride, or polyvinyl acrylonitrile, although any such plastic can be used. Additionally, other materials can be used including but not limited to glass products, resins, fiberglass, metals, ceramics or any rigid material.  
         [0049]     The hinge  335  of many embodiments is made of a metallic or nonmetallic pin formed from any of the materials discussed above that is either separate from or integral with the operating lever  330 . In such embodiments, the pin forming part of the hinge  335  is inserted into a hole formed in the lever  330 . In some embodiments, the hinge  335  is molded or integrated into the lever  330  and fits into holes formed in the termination insulator  318  or other structure.  
         [0050]      FIGS. 4, 4   a  and  4   b  illustrate a wiring device  400  having an alternate integral actuator. These embodiments also have terminal blades  405 , an insulating insert  408 , an insulating backshell  420 , and a termination insulator  418 , as those parts are described above. In this embodiment, the integral, insulating and hand-operated operating actuator is an operating pin  430  that slides within the termination insulator  418  to activate the cage clamp  410 . The pin  430  of many such embodiments is a longitudinal shaped part having a first operating end  435  and a second actuating end  440  opposite the operating end  435 . The pin  430  extends through the termination insulator  418  with the operating end  435  extending outside the termination insulator  418  and the actuating end  440  remaining within the termination insulator  418 .  
         [0051]     The operating end  435  of the pin  430  is designed to allow a user to engage and disengage the pin  430  and thereby engage and disengage the cage clamp  410 . In the embodiment illustrated, the operating end is similar to the widened or flattened end of a nail or a pin. Such a flattened area creates a wider area to allow operation by a user by hand and without the need of a tool. Modifications of the illustrated embodiment include larger of the widening of the operating end such that the operating end extends beyond the termination insulator  418  to provide an extending edge to disengage the pin  430 . Other embodiments of the wiring device  400  utilize different shapes of the operating end  435  that have ridges or other forms to allow the user to grip and apply extra disengaging force if required.  
         [0052]     The activating end  440  of the pin  430  is designed to function as a cam in that as the pin  430  is inserted into the termination insulator  418  it applies a lateral engaging force to the cage clamp  410 . The conversion of the longitudinal motion of the pin  430  into the lateral engaging force needed to operate the cage clamp  410  is the main function of the activating end  440 . As illustrated in  FIGS. 4 and 4   a,  when the pin  430  is pushed inward into the termination insulator  418 , the activating end  440  begins to apply activating force to engage the cage clamp  410 . The shape and size of the activating end  440  can also limit the amount of activating force applied to the cage clamp  410 . By limiting the amount of force that can be applied to the cage clamp  410  with the design of the activating end  440 , it is possible in these embodiments to prevent over-compressing and plastically deforming the cage clamp  410 . Again, preventing such over-compression increases the reliability of such wiring devices  400  because the plastic deformation of resilient springs leads to released resilience and clamping force, which can cause failure of wiring devices.  
         [0053]      FIG. 4   a  illustrates the full insertion of the pin  430  into the termination insulator  418  thereby fully engaging the cage clamp  410 . This embodiment also illustrates an extended operating end  435  that extends beyond the end of the termination insulator  418  so that it can be easily disengaged. As can be illustrated by  FIG. 4 , the inside depth  422  of the backshell  420  is designed such that the pin  430  can be in the fully retracted position as in  FIG. 4  when the backshell  420  is installed. In such embodiments, the cage clamp  410  applies its clamping force to the mated connection when the pin  430  is retracted, and therefore, the backshell  420  provides such room.  
         [0054]     The pin  430  of the embodiment illustrated in  FIGS. 4, 4   a  and  4   b  can be made of any rigid material, and may be cylindrical or polygonal in shape and cross-section. The pin  430  of some embodiments includes ridges either along its length where it passes through an opening in the termination insulator  418  or at the activating end  440  that indicate one or more positions to the user. For instance, one ridge can indicate a point at which the pin  430  is fully inserted or another to indicate when the pin  430  is fully extracted.  
         [0055]     In some embodiments, when the pin  430  is fully extracted, the length of the pin  430  is such that the operating end  435  forms a stripping gauge. The distance between the termination insulator  418  and the raised or sharpened gauge point of the operating end  435  indicates to a user the correct length of insulation to be stripped from a wire that is to be inserted into a lead hole  450  and mated with the terminal blade  405 . The lead hole  450  is an opening in the termination insulator  418  through which a bare lead to be connected to the wiring device  400  is inserted. The lead hole  450  is aligned with the passage in the cage clamp  410  that is formed when the cage clamp  410  is activated. A raised or sharpened shape can also be formed on embodiments having a gauge point at the operating end  440  that can be used to score or mark the insulation of a conductor wire prior to stripping, thereby eliminating the use of a marking pen and reducing errors caused by visual estimation of this distance.  
         [0056]      FIG. 4   b  represents an alternate embodiment of the wiring device  400  of  FIGS. 4 and 4   a  still utilizing an operating pin  430  for engaging and disengaging the cage clamp  410 . In the embodiment illustrated, the cage clamp  410  is reversed such that the passage in the cage clamp  410  is adjacent to the lead hole  450  in the termination insulator  418 . The pin  430  of the embodiments illustrated in  FIGS. 4, 4   a  and  4   b  can be made of any rigid material capable of supporting the forces and stresses that each design of the pin  430  will produce when the pin  430  is engaged and disengaged. Some embodiments utilize electrically insulating and thermally stable materials such as strong plastics. Other embodiments use metals, alloys, ceramic, wood-based or paper-based products, thermosets, fiberglass, epoxy or any other suitable material.  
         [0057]      FIGS. 5, 5   a,    5   b  and  5   c  illustrate another embodiment of a wiring device  500  that has an integral hand-operable actuator. The integral actuator of these embodiments includes a hinged or pinioned operating lever  530 . Embodiments as illustrated in  FIGS. 4, 4   a  and  4   b  include many of the components described above, such as terminal blades  505 , a cage clamp  510 , a termination insulator  418 , a backshell  520  and a lead hole  550 . The descriptions of the corresponding parts above apply here as well, and no further description will be provided. The integral actuator of embodiments illustrated is a longitudinal lever  530  attached to a cam  540 , which is mounted to the termination insulator  418  via a pivot joint  535  along a line that does not run through the centroid of the cam  540 . This offset mounting of the cam  540 , allows the cam  540  to rotate in an eccentric manner about the pivot joint  535 . The eccentric rotation leads to a travel of the cam  540  that is capable of applying operative engaging force to the cage clamp  510 .  
         [0058]     As illustrated in  FIGS. 5, 5   b  and  5   c,  the various positions of the lever  530  along the complete range of its rotation fall in to three categories.  FIG. 5  illustrates the first category where the cam  540  is fully disengaged from the cage clamp  510 .  Figure 5   c  illustrates another category where the cam  540  is fully engaged with the cage clamp  510  thereby fully compressing the cage clamp  510 . Finally,  FIG. 5   b  illustrates a final category including all the positions between or other than those illustrated previously, where the cam  540  is in a midway position between the fully engaged and fully disengaged states.  
         [0059]     In the position illustrated by  FIG. 5 , the lever  530  is in its fully disengaged orientation. In this orientation, the cam  540  is not applying any engagement force to the cage clamp  510  so that the cage clamp  510  can exert full retentive force. Therefore, in this orientation, the cage clamp  510  exerts the full retentive force to a wire lead (not shown), if one resides in the lead hole  550 .  
         [0060]     In many such embodiments, the lever  530  in this position is in the only orientation that allows the insulating backshell  520  to be assembled onto the rest of the wiring device  500 . The presence of the backshell  520  on the wiring device  500  also prevents the lever  530  from traveling off its fully disengaged position, thereby ensuring that the cam  540  is not rotated to engage the cage clamp  510 . This provides a measure of certainty that the connection made by the cage clamp  510  will remain secure. A plane  560  the interior surface of the backshell  520  travels while assembled onto the wiring device  500  is shown that illustrates how the lever  530  of such embodiments will not interfere with the assembly of the backshell  520  only when the lever is fully disengaged. This not only ensures that the wiring device is fully assembled when the cage clamp  510  is correctly retaining the wire lead to be connected (not shown), but also ensures that the lever  530  and cam  540  will remain disengaged from the cage clamp  510  after assembly of the wiring device  500 . Such design characteristics provide a level of confidence in the connections made to the wiring device that were heretofore unattainable.  
         [0061]     The pivoting action of the lever  530  can be achieved through many mechanisms or structures as described for the lever  330  of  FIG. 3  and all of the pivoting joints described therein apply equally to these embodiments. For instance, in some embodiments the pivot joint  535  consists of two protrusions extending from the termination insulator  518  on either side of the cam  540 , while two corresponding cavities are formed in corresponding and adjacent positions on the cam  540 . In such embodiments, when the cam  540  is inserted into the termination insulator  518  the two shapes will snap into the cavities in the cam  540 , thereby forming the pivot joint  535 . Alternatively, the protrusions can extend from the cam  540  and the cavities can be formed into the termination insulator  518 . The protrusions can be cylindrical, hemispherical, conical, or any section or modification thereof or any other geometric shape that can provide the appropriate functions. Some embodiments utilize a metallic or nonmetallic hinge pin (not separately shown). The hinge pin can either be separate from and inserted through the cam  540  and held in place by the termination insulator  518 , or it can be molded or integrated into the cam  540  and/or the termination insulator  518 . In some such embodiments, the pivot joint  535  is a rivet running through the cam  540  and engaged with the outside of the walls of the termination insulator  518 . Many more mechanisms can be used for the pivot joint  535  as well. Furthermore, the lever  530  can be manufactured as either a separate piece or integral with cam  540 . In some embodiments, the lever  530  consists of multiple parts fitted together to fulfill the function described herein. Some embodiments include various shapes or surface treatment on the lever  530  to increase the grip a user is able to apply to the lever  530 .  
         [0062]      FIG. 5   a  illustrates the wiring device of  FIG. 5  rotated 90 degrees about an axis running along the center of the wiring device  500  and backshell  520 . The embodiment illustrated does not have the backshell  520  assembled but illustrates the lever  530  extending from the termination insulator  518 . In this embodiment, the lever  530  is in the fully disengaged position. The lever  530  can be shaped, as illustrated, to extend beyond the termination insulator  518  in order to ease operation by the user. The lever  530  can also be shaped such that the end does not extend beyond the termination insulator  530  to deliberately make operation more difficult.  
         [0063]     In the second position of the embodiment as illustrated in  FIG. 5   b,  the lever  530  has been rotated from its fully disengaged position to the floating mid-position where the cam  540  can begin to contact or even apply engagement force to the cage clamp. An operating force F is applied to the lever  530  to move it from its first position illustrated in  FIG. 5  to its second position as illustrated in  FIG. 5   b.  Due to the design of the cam  540  and the physical properties of cams in general, a mechanical advantage can be created whereby the operating force F is amplified as it is applied to the cage clamp  510 . In certain robust embodiments utilizing strong cage clamps  510 , this allows a user to comfortably apply the operating force F necessary to produce the proper engagement of such cage clamps  510 . The use of a cam  540 , as illustrated in  FIGS. 5, 5   b  and  5   c,  also limits the maximum force and displacement that is applied to the cage clamp  510 . The maximum travel of the cam  540  can easily be designed into a particular embodiment, thereby reducing or eliminating the possibility of plastic deformation of the cage clamp  540 . Again, reducing or removing the possibility of plastic deformation of the cage clamp  540  leads to increased reliability of the wiring device  500 .  
         [0064]     In certain embodiments, ridges or other structures are applied to the cam  540 , the termination insulator  518 , and/or other structures to create indications of the various positions of the lever  530 . For instance, in some embodiments one ridge is present on the termination insulator  518  and a mating ridge is present at one angular position of the cam  540  extending along the thickness of the cam  540 . Such ridges are designed as such common position indicators to identify when the cam  540  is fully disengaged. Additional ridges or other structures can be added to indicate other positions to the user as well.  
         [0065]     In the position illustrated by  FIG. 5   b,  the operator is preparing to provide engaging force to the cage clamp  510  by rotating the lever from the disengaged position. However, this position also prevents the backshell  520  from being assembled onto the wiring device  500 . In embodiments where more than one conductor or lead of a multiconductor cable is terminated to such a wiring device  500 , any or every operating lever  530  that is not properly positioned in the fully disengaged orientation will prevent the final assembly of the backshell  520 . This also alerts the assembler to the improper assembly.  
         [0066]     In the third position illustrated by  FIG. 5   c,  the lever  530  has been rotated to the fully-engaged position. In this position, the cam  540  is in its most eccentric orientation, with respect to the cage clamp  510  and therefore is applying full engaging force to the cage clamp  510 . However, as noted above, the maximum eccentricity and the full engaging force are designed in many embodiments to reliably stay within elastic deformation ranges for each particular cage clamp  510  that is used. As also described above, the pivot joint  535  is positioned so as to provide a great mechanical advantage where necessary, thereby reducing potential injury to assembly personnel. A significant mechanical advantage can be very useful in large connectors/wiring devices, where the force necessary to fully engage the cage clamp  510  is very high. In many embodiments, as the cam  540  is rotated toward a position where maximum engaging force is applied to the cage clamp  540 , the area on the cam  540  contacting the cage clamp  510  is generally in alignment with the pivot joint  535  and the longitudinal axis of the lever  530 . This relationship makes it more difficult for the resilient force of the cage clamp  510  to tend to rotate the cam  540  and provide feedback to the user through the lever  530 . This creates a stable position and prevents the lever  530  from violently snapping back to the disengaged position due to the resilient force of the cage clamp  510  if the lever  530  is released by the user while in the fully engaged position. This stable position allows the user to insert a conductor wire into the lead hole  550  without having to apply continuous force to the lever  530 , thereby easing usage of the wiring device  500 . Ridges, as described above, or additional or alternative structures, can be added to provide positive feedback that the lever  530  is in the fully engaged position and to add to the stability of that position of the lever  530  and cam  540 .  
         [0067]     The lever  530 , the cam  540  and the termination insulator  518  are designed to prevent access to and contact with the cage clamp  510 , the terminal blade  505  or any other electrically-energized components on the inside of the wiring device  500 , regardless of the position of the lever  530 . The components described herein can be manufactured of any material of sufficient strength and rigidity to achieve the functions described herein. Many embodiments utilize electrically insulative and thermally stable materials for the cam  540 , lever  530 , pin joint  535  and termination insulator  518 . In certain embodiments the cam  540  and lever  530  are made of strong plastic materials, however these items, the pivot joint  535 , the backshell  520  and the termination insulator  518  can be made of any suitable thermoplastic, thermoset, epoxy, resin, fiberglass, metal, alloy, ceramic, wood-based or paper-based product or any other material or combinations of these or other materials. Additionally, these items can be made from different materials from one another. The cage clamp  510  and termination blades  505  of many embodiments are made of metals such as, but not limited to, steel, brass, and various alloys, but can be made of any material having the appropriate strength and resilience and capable of conducting electric current. An electrically conductive material can be coated onto other materials that are used, if required.  
         [0068]      FIGS. 6 and 6   a  illustrate alternative embodiments of the wiring devices 600 to those  FIGS. 5, 5   a,    5   b  and  5   c.  In these alternative embodiments, the termination insulators  618  are formed such that the cam  640  is not proximate to, but rather is distant from the cage clamp  618 . In such embodiments, the cam  640  does not directly engage and disengage the cage clamp  610 . Rather, the cam  640  applies its force to a push rod  660  positioned within the termination insulator  618  between the cam  640  and the cage clamp  610 . The push rod  660  is an elongated generally cylindrical rod having ends that contact the cam  640  and the cage clamp  610  to transmit force and motion from the cam  640  to the cage clamp  610 .  
         [0069]      FIG. 6  illustrates a lever  630  forming part of an actuator for the wiring device  600  in the mid-position between fully engaged and fully disengaged. The lever  630  has been rotated such that the cam  640  is beginning to apply a force to the push rod  660 , and in return the push rod  660  is beginning to apply an engaging force to the cage clamp  610 . The push rod  660  can serve the insulating functions allowing the cam  640 , pivot joint  635  and the lever  630  to be made of metal as well as any of the other materials described above. In such embodiments, the push rod  660  is made of or coated with an electrically insulative material. The illustrated push rod  660  is shown as an example and any length, shape or sized item can be used that is capable of transferring the force applied from the cam  640  to the cage clamp  610 . Such variations allow the actuator of these embodiments to be used on a variety of wiring devices and configurations including NEMA and other types.  
         [0070]      FIG. 6   a  illustrates the wiring device  600  having the lever  630  rotated all the way to the fully engaged position, thereby positioning the push rod  660  so as to fully compress the cage clamp  610  allowing a lead to be inserted into or removed from the lead hole  650  to make or undo an electrical connection with the terminal blade  605 . The embodiments illustrated otherwise include all of the functionality of the previously described embodiments.  
         [0071]      FIG. 7  is a perspective and partial cutaway view of the partially assembled embodiment of  FIGS. 5, 5   b  and  5   c.  In the embodiment illustrated, the cam  710  and lever  730  are mounted in a recess  745  formed in the insulating insert  708  in proximity sufficient to engage and disengage the cage clamp  710  as it is rotated. The opening  755  in the cage clamp  710  is radially misaligned with the wire lead hole  750  through the insert  708  such that when the lever  730  is operated and the cage clamp  710  is engaged, the opening  755  will then be deflected to align with the wire lead hole  750  in the insert  708 . When the lever  730  is returned to its rest position as illustrated, after a wire lead (not shown) is inserted, the cam  740  releases the cage clamp  710  and allows it to secure the lead against the terminal  705  held against another portion of the cage clamp  710 . In the embodiment illustrated, the lever  730  and cam  740  are reversed from their orientation in  FIG. 5 , as they are situated such that the lever  730  is facing the forward end of the insert  708 , the end where the terminal  705  extends out of the insert  708 . Such design variations are utilized to allow the insert  708  to be implemented into many different types of wiring devices. This is an illustration of just one embodiment, and many variations can be used in many different applications, which include additional design elements such as those illustrated and described that are suitable to improve the performance of each particular embodiment.  
         [0072]      FIGS. 8   a  and  8   b  illustrate an alternative embodiment of the wiring device  700  embodiment illustrated in  FIG. 7 .  FIG. 8   a  is a partial cutaway side view of the alternative embodiment, while  FIG. 8   b  is a perspective and partial cutaway view of the embodiment of  FIG. 8   a.  This embodiment illustrates one way in which an inserted lead  855  can be secured against the terminal blade  805  and the lower edge of the cage clamp  810 . In this embodiment, a retainer  870  is utilized to control the location of the cage clamp  810  inside the termination insulator  818 . The retainer  870  of this embodiment is a cylindrical strut running across the width of the illustrated portion of the termination insulator  818 . The retainer  870  of this embodiment is also illustrated as being located near the dynamic bend  812  of the cage clamp  810 , however in embodiments utilizing retainers  870  to increase control of the position of the cage clamp  810 , the retainer  870  can be located at any position in the termination insulator  818  or the insert  808  that is capable of aiding in the control of the position of the cage clamp  810 . In many embodiments, a retainer  870  is not utilized because the shape of the interior of the termination insulator  818  restricts the positioning of the cage clamp  810  to only the desired position and orientation.  
         [0073]     As illustrated in both  FIGS. 8   a  and  8   b,  a lead  855  is stripped of its insulation to the proper depth and is inserted into the lead hole  850  when the cage clamp  810  is engaged by the cam  840  and the lever  830 . The mounting of the pivot joint  835  in a location offset from the centroid of the cam  840  ensures that the rotation of the cam  840  by the lever  830  will create the engaging force necessary to engage the cage clamp  810  and displace the lead opening  855  to align with the lead hole  850  to accept an inserted lead  880 . When the lead  880  is inserted into the channel formed by the alignment of the lead hole  850 , the lead opening  855  and the edge of the terminal blade  805 , the lever  830  can then be moved to the disengaged position as illustrated, thereby rotating the cam  840  to the fully disengaged position and allowing the cage clamp  810  to apply a resilient retaining force to the lead  880  to retain it in the wiring device  800 . This contact formed by the resilient force of the cage clamp  810  directed to hold the lead  880  against the terminal blade  805  forms a much more reliable and secure termination than is available in existing wiring devices. The thermal expansion and contraction, or cycling, of the wiring device  800  will not reduce the retaining force of the cage clamp  810  over time as it does in existing devices.  
         [0074]     The use of electrically insulating materials for the cam  840  and/or the lever  830  increases safety. If the lead  880  is purposefully or inadvertently left energized during assembly, the user is insulated from the lead during the engagement and disengagement of the cage clamp  810 , thereby reducing the possibility of electrical shock. This can also increase the degree of safety available when it is desirable or necessary to make “hot” connections with the lead(s)  880  energized.  
         [0075]     The foregoing description details certain embodiments of the invention. It will be appreciated, however, that no matter how detailed the foregoing appears in text, the invention can be practiced in many ways. As is also stated above, it should be noted that the use of particular terminology when describing certain features or aspects of the invention should not be taken to imply that the terminology is being re-defined herein to be restricted to including any specific characteristics of the features or aspects of the invention with which that terminology is associated. The scope of the invention should therefore be construed in accordance with the appended claims and any equivalents thereof.  
         [0076]     Many embodiments have been described herein. Many of the embodiments relate specifically to NEMA wiring devices. It should be known that the inventive elements described in those and other embodiments can be applied easily by those of skill in the art to any lead terminating application. The materials used for such embodiments are a matter of design choice and can be selected by one of ordinary skill in the art based upon the desired characteristics of the particular embodiments.