Patent Publication Number: US-7909633-B1

Title: Wire connection apparatus

Description:
FIELD OF THE DISCLOSURE 
     The present disclosure relates generally to electrical wiring and, in particular, to a convenient terminal wire block. 
     TECHNICAL BACKGROUND 
     Terminal wire blocks are widely used to connect electrical wires to printed wiring boards (PWBs) or printed circuit boards (PCBs), to securely couple pairs of wires, and to otherwise provide reliable electrical contacts. In general, it is known to use either spring clamps or screw clamps as terminal wire blocks to secure electrical wires in a fixed position. 
     Spring wire clamps typically include a housing and a spring (or a similar elastic component) to which a force is manually applied as a wire is inserted into the clamp. Once released, the spring exerts a force on the wire to push the wire against one of the walls of the housing. It is also known to install an elastic element on the wire to interact with a clamp housing of a standard size. For example, a typical personal computer includes a cage terminal to receive an Ethernet cable that includes a flexible plastic strip, bent to define an acute angle, at one or both ends. The plastic strip and the cage terminal together define a push-in terminal that does not require screws, bolts, or other fasteners. 
     By contrast, screw clamps typically include a housing and an externally threaded fastener such as a screw operatively connected to the housing. A technician places a wire inside the housing and tightens the fastener to push the wire against one of the walls of the housing. Accordingly, screw clamps usually require the use of a tool such as a screwdriver. 
     Some technicians prefer spring clamps while others prefer screw clamps. In addition to personal preferences, certain applications make spring clamps preferable because spring clamps normally do not require special tools or room to maneuver such tools. Moreover, spring clamps typically are better suited for connecting wires on or adjacent to vibrating devices, as threaded connections (e.g., a screw and a nut) tend to loosen in response to vibration. On the other hand, spring clamps may include easily breakable components such as plastic strips, or may age faster as springs or similar flexible components lose rigidity or elasticity. 
     SUMMARY 
     A terminal wire block includes two independently operable wire clamps for securing a wire in a fixed position. In at least some of the embodiments, the two independently operable wire clamps use different mechanisms, such as a spring mechanism and a screw mechanism, to hold the wire in place. 
     In an embodiment, the terminal wire block includes a screw clamp and a spring clamp positioned behind the screw clamp, so that an exposed end of the wire first passes through the screw clamp to reach the spring clamp. The spring clamp includes a cage and a flexible spring finger biased toward one of the walls of the cage, so that the spring finger must be bent to allow the wire to reach the inside of the cage. By contrast, the screw clamp includes a cage with a threaded opening and an externally threaded fastener to mate with the opening of the cage to define a narrower or wider opening in the direction of movement of the wire through the cage in response to tightening or loosening the externally threaded fastener, respectively. 
     To insert a wire into the spring clamp, a technician pushes an exposed end of the wire through the screw clamp to reach the flexible spring finger, and applies sufficient pressure to the wire to displace one end of the spring finger relative to its equilibrium position, and allow the wire to reach the inside of the cage of the spring clamp. When the technician stops applying pressure to the wire, the spring finger pushes the wire toward one of the walls of the cage and thereby secures the wire in a fixed position. 
     Optionally, the technician subsequently tightens the externally threaded fastener of the screw clamp to hold the wire more firmly in place and thus provide additional integrity to the corresponding electrical contact. As another option, the technician uses only the screw clamp. In this case, the technician pushes the wire inside the cage of the screw clamp but not far enough, or with a sufficient force, to displace the spring finger. 
     To remove the wire from the terminal wire block when only the screw clamp is engaged, the technician loosens the externally threaded fastener and pulls out the wire. To remove the wire from the terminal wire block when both the spring clamp and the screw clamp are engaged, the technician may also operate a push down button which applies pressure to the spring finger in the direction opposite to the bias of the spring finger, or reach the spring finger with a tool such as a screwdriver via a corresponding opening. 
     In some embodiments, a terminal wire block with a small foot print includes a spring clamp having a spring and a screw clamp having a fastener operatively connected to the spring, so that the spring is deflected in response to pressure applied to the fastener. Once the spring clamp secures a wire in a fixed position, a technician may also engage the screw clamp by threading or otherwise tightening the fastener. In at least some of the embodiments in which the fastener is adapted to communicate pressure to the spring, the spring clamp and the screw clamp share a common cage. Further, the spring in some embodiments may have a first bias in a direction opposite to the direction in which the fastener is threaded, and a second bias approximately perpendicular to the first bias to better guide pressure applied to the fastener. 
     In some embodiments, multiple terminal wire blocks, each having a spring clamp and a screw clamp, are aligned on a circuit board to define a multiple-input connector or a connector array. In one such embodiment, multiple terminal wire blocks form several rows, with the back rows being progressively elevated relative to the front rows to provide convenient and secure access to each terminal wire block. 
    
    
     
       DETAILED DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a terminal wire block having two independently operable clamps. 
         FIG. 2  is another perspective view of the terminal wire block of  FIG. 1  with a cover removed. 
         FIG. 3  is a side view of the terminal wire block of  FIG. 1 . 
         FIG. 4  is another perspective view of the terminal wire block of  FIG. 1 . 
         FIG. 5  is a perspective view of a wire connector in which several instances of the terminal wire block of  FIG. 1  are arranged in a two-row array. 
         FIG. 6  is a perspective view of a terminal wire block in which a fastener is combined with a push button. 
         FIG. 7  is another perspective view of the terminal wire block of  FIG. 6  with a cover removed. 
         FIG. 8  is a side view of the terminal wire block of  FIG. 6 . 
         FIG. 9  is a perspective view of another embodiment of a terminal wire block in which a fastener is combined with a push button. 
         FIG. 10  is a perspective view of a wire connector that includes two instances of the terminal wire block of  FIG. 9 , arranged in respective upper and lower rows. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-4  illustrate an example of a terminal wire block  10  for securing an electrical wire  12  in a fixed position using one or both of two independent mechanisms to complete an electrical contact, for example. In particular, the terminal wire block  10  includes a spring clamp  14  and a screw clamp  16  so that the wire  12  may be secured using only the spring clamp  14  or only the screw clamp  16 . However, if desired, a technician may also secure the wire  12  using both of the clamps  14  and  16  to provide additional integrity and security to the electrical contact. 
     The terminal wire block  10  may include a terminal base  20  and an external cover  22 . In general, the terminal base  20  may be mounted on a horizontal, vertical, or inclined surface. In some embodiments, the terminal base  20  may be soldered to a circuit board or another component. Alternatively, the terminal base  20  may include one or several pins (not shown) for mounting on the circuit board. The terminal base  20  may be manufactured from a rigid non-conductive material such as plastic, for example. However, the terminal base  20  in other embodiments may be made of metal or another conductive material. In addition to fulfilling the structural functions discussed in more detail below, a conductive terminal base  20  may serve as a conductive path between the wire  12  and another electrical contact such as a wire or a circuit board contact. 
     In the embodiment of  FIGS. 1-4 , the terminal base  20  is a relatively thin sheet with a section bent or molded to define a cage  24  of the spring clamp  14 . A flexible spring finger  26  (best shown in  FIG. 4 ) is disposed inside the cage  24  and is biased in the direction D 1 , i.e., toward the upper wall of the cage  24 . More specifically, the spring finger  26  is sloped opposite to a direction D 2  in which the wire  12  enters the terminal wire block  10 , so that the wire  12  bends the spring finger  26  toward the bottom wall of the cage  24  (i.e., opposite to the direction D 1 ) when entering the spring clamp  14 . The finger spring  26  thus defines a mechanical push-in terminal of the terminal wire block  10 . Once the wire  12  is inside the cage  24 , the spring finger  26  pushes the wire  12  toward the upper wall of the cage  24 . Thus, when pressure is no longer applied to the spring finger  26  by way of the wire  12  in the direction D 2 , the spring clamp  14  holds the wire  12  securely in place. 
     The spring finger  26  generally may be manufactured using a resilient material having a memory, so that the spring finger  26  has a tendency to return to its original shape once deformed. In an embodiment, the spring finger  26  is also conductive to provide an electric contact between the wire  12  and another wire or the cage  24 , for example. To this end, the spring finger  26  may be made of a metal or alloy. 
     As best illustrated in  FIG. 4 , the spring finger  26  may be welded, soldered, glued, or otherwise fastened to the bottom wall of the cage  24  at a contact point  28 . Further, in the embodiments including a conductive spring finger  26 , an exposed section of a second electrical wire (not shown) may be fastened to the spring finger  26  at the contact point  28  to complete a current path between the wire  12  and the second wire. In other embodiments, the spring finger  26  may be soldered directly to the circuit or wire board on which the terminal base  20  resides. 
     To release the wire  12  held by the spring clamp  14 , a push button  34  is operated to apply pressure to the spring finger  26  via a pair of actuating levers or legs  36  in the direction opposite to D 1 . In other embodiments, the spring clamp  14  may not include the push button  34  at all, and a technician may apply pressure directly to the spring finger  26  using a screwdriver or another suitable tool, for example. Once the spring finger  26  is depressed, the wire  12  can be easily pulled out of the spring clamp  14 . The cage  24  accordingly includes a pair of openings  38  to receive the respective legs  36 . 
     The screw clamp  16  is disposed in front of the spring clamp  14  relative to the opening through which the wire  12  in inserted into the terminal wire block  10 . In other words, the wire  12  passes through the screw clamp  16  to reach the spring clamp  14 . In the embodiment illustrated in  FIGS. 1-4 , the screw clamp  16  includes a U-shaped bracket  40  and an L-shaped bracket  42  that define a cage  44  (best shown in  FIG. 2 ). The brackets  40  and  42  include respective aligned openings  46  to receive a fastener  50  having a head  52  and a work end  54 . In general, the fastener  50  may be of any desirable type, and the head  52  accordingly may be selected to mate with a single-blade, Phillips, Allen, or any other type of a screwdriver. The work end  54  is preferably flat to avoid damaging the wire  12 , although fasteners with non-flat or even sharp work ends also may be used. 
     If the fastener  50  is a screw, a bolt, or another type of a fastener with an external threaded surface, the internal surface of each of the openings  46  may include corresponding threads. The fastener  50  may thus couple the brackets  40  and  42  to each other, as well as serve as an actuating element of the screw clamp  16 . Of course, it is also possible to provide the cage  44  as an integral element which, in turn, may also may be integral with other components of the terminal wire block  10 . 
     To engage the screw clamp  16  when the wire  12  is inside the terminal wire block  10 , a technician may tighten the fastener  50  to thereby reduce the distance between the work end  54  and the bottom wall of the cage  44 . In this manner, the screw clamp  16  applies pressure to the wire  12  in the direction opposite to D 1 . To evenly distribute pressure applied to the wire  12 , and to prevent damage to the threads of the wire  12 , a plate  56  may be attached to the work end of the fastener  50 . The technician may release the wire  12  from the screw clamp  16  by loosening the fastener  50  (i.e., by driving the work end  52  in the direction D 1 ). 
     It will be noted that the spring clamp  14  may be operated independently of the screw clamp  16 . In other words, a technician may push the wire  12  through the cage  44  to engage the push-in terminal of the spring clamp  14 . Once engaged, the spring clamp  14  will hold the wire in place irrespective of the position of the fastener  50 . Alternatively, the technician may choose not to push the wire  12  through to the spring clamp  14  and may engage only the screw clamp  16 . As yet another alternative, the technician may engage both the spring clamp  14  and the screw clamp  16  if additional contact integrity or security is desired. In this case, the clamps  14  and  16  apply pressure to the wire  12  along the direction D 1  and in the direction opposite to D 1 , respectively, thereby providing a tight and secure connection. 
     In the embodiment illustrated in  FIGS. 1-4 , the external cover  22  is a bracket having a front plate  60  with an opening to receive the wire  12 , and an upper plate  62  with two openings to receive the push button  34  and the fastener  50 , respectively. The plates  60  and  62  may be perpendicular to each other. If desired, the external cover  22  may be made of a less durable material than the terminal base  20 . 
     In an embodiment, the head  52  of the fastener  50  may be shaped so as to retain the cage  44  in a fixed position within the terminal wire block  10  without rigidly securing one or both of the brackets  40  and  42  to the terminal  20 . As best illustrated in  FIG. 3 , the thickness t of the head  52  may be greater than the distance d between the bottom of the cage  44  and a corresponding section of the terminal base  20 . It is thus possible to loosely connect the cage  44  to other components of the terminal wire block  10 , thus simplifying the manufacture and assembly of the terminal wire block  10 . 
     It is also possible to provide a single component (e.g., an extended terminal base) in which the terminal base  20  is integral with the cage  44 . Further, if such an extended terminal base is manufactured from a conductive material, and if the spring finger  26  is soldered to the extended terminal base, the cage  44  may be at the same electric potential as the contact point  28 . In this manner, the terminal wire block  10  may electrically connect the wire  12  to an electrical wire connected at the contact point  28  even if only the screw clamp  16  is engaged. Alternatively, an electrical wire may be connected to the screw clamp  14  at the top of the cage  44 . 
     Generally speaking, some or all of the components of the terminal wire block  10  may be manufactured using metal extrusion, injection molding of plastic, cutting and bending of sheet metal, or any other suitable techniques. The selection of suitable material for some of these components may depend on the desired electrical connections within the terminal wire block  10 . For example, it may be necessary to manufacture the terminal base  20  from a metal or metal alloy if the terminal base  20  serves as a conductive path between the wire  12  and another wire or the PWB. 
     In one embodiment, the terminal wire block  10  is compatible with a 0.2″ terminal pitch, and the wire  12  is in the range between the No. 24 American Wire Gauge (AWG) stranded (i.e., measured along the cross-sectional area of the conductive strands) wire to 12 AWG solid core wire. As best illustrated in  FIGS. 1 and 2 , the terminal wire block  10  receives an exposed end of the insulated wire  12 . Of course, the terminal wire block  10  generally may be manufactured in compliance with any desired terminal pitch, wire size, circuit board standard, etc. 
     It will be appreciated that the terminal wire block  10  is discussed above by way of example only. Several additional features and alternatives to the embodiment of  FIGS. 1-4  are discussed below. In general, a terminal wire block having at least two independently operable clamps may include none, one, or several of these features. 
     In one aspect, it is not necessary for the fastener  50  to apply pressure to the wire  12  in the direction opposite to D 1 . As one alternative, the screw clamp  16  may push the wire  12  in the direction D 1  when the technician tightens the fastener  50 . In another alternative, the screw clamp  16  may be positioned so as to direct the pressure from the fastener  50  perpendicularly to both D 1  and D 2 . Other orientations of the screw clamp  16  and/or the fastener  50  are also possible. 
     Further, the spring clamp  14  may include a biasing element other than the spring finger  26 . For example, the biasing element may be a spring, a coil, or another flexible element. Also, the biasing element may be biased in any direction other than D 1  that results in the wire  12  being pressed against a wall of the corresponding cage and thereby being held in place. 
     Still further, the fastener  50  in another embodiment may be combined with the push button  34  to reduce the foot print of the terminal wire block  10 . The spring clamp  14  and the screw clamp  16  may accordingly share a cage to hold the wire  12 . However, the respective mechanisms of the clamps  14  and  16  are preferably independently operable. For example, the head  52  of the push button  34  may include an aperture, and the push button  34  may include an internal threaded surface, to receive and mate with the external threads of the fastener  50  along the direction D 1 . 
     In yet another aspect, a terminal wire block similar to the terminal wire block  10  may include more than two wire clamps implementing different wire clamping techniques, with at least two of the wire clamps being independently operable. 
     Also, the spring clamp  14  in some embodiments may be disposed in front of the screw clamp  16  relative to the opening through which the wire  12  in inserted into the terminal wire block  10 . To reach the cage  44  of the screw clamp  16 , the wire  12  may be pushed against and past the spring finger  26  of the spring clamp  14 . Thus, in this embodiment, the spring clamp  14  may be engaged automatically when the wire  12  is secured using the screw clamp  16 . 
     Referring to  FIG. 5 , multiple terminal wire blocks identical or similar to the terminal wire block  10  may define a multiple-input connector  100 . In this example, the multiple-input connector  100  includes a front row  102  and an elevated back row  104 , each having eight openings  105 / 1 ,  105 / 2 , . . .  105 / 16  into respective wire terminals, which together define a set of wire terminals  106 / 1 ,  106 / 2 , . . .  106 / 16 . The elevation of the back row  104  relative to the front row  102  provides convenient access to the wire terminals of the back row  104 . Each of the wire terminals includes a spring cage with a corresponding push button  109 / 1 ,  109 / 2 , . . .  109 / 16  and a screw cage with the head of a fastener accessible via a corresponding opening  108 / 1 ,  108 / 2 , . . .  108 / 16 . The multiple-input connector  100  may be enclosed in a protective housing  110  with a base  112  mountable on a circuit or wire board, or on any other surface. 
       FIG. 6  illustrates a terminal wire block  150  that includes a spring clamp  152  and a screw clamp  156  that share a common cage  158  (best shown in  FIG. 7 ). In this embodiment, the spring clamp  152  includes a spring  154 , and the screw clamp  156  includes a fastener  159  through which a technician may apply pressure to the spring  154 . Thus, in a sense, the fastener  159  has respective functions in both the spring clamp  152  and the screw clamp  156 . 
     With continued reference to  FIG. 6 , the terminal wire block  150  may include a terminal base  160  and an L-shaped cover  162  with an opening  164  through which a wire may enter the terminal wire block  150 , and another opening  166  through which a tool such as a screwdriver may access the fastener  159 . As explained in more detail below, a technician can actuate the spring  154  via the opening  166  and the fastener  159 . As compared to the embodiment discussed with reference to FIGS.  1 - 4 , the terminal wire block  150  has a smaller foot print and requires fewer parts. Moreover, the terminal wire block  150  allows a technician to operate each of the spring clamp  152  and the screw clamp  156  using the same screwdriver (or another suitable tool). 
     As best illustrated in  FIG. 7 , the base  160  may be shaped as a capital letter “F” with a vertical support wall  172  and a middle shelf  174  to which the spring  154  may be soldered, glued, or otherwise fastened. The spring  154  may be, for example, a flat spring shaped as a capital letter “G”, with the inward protrusion aligned with the middle shelf  174 , and the loop section below the inward protrusion defining the cage  158 . The spring  154  includes an opening  180  approximately at the level of the middle shelf  174  through which an exposed end of a wire can enter the cage  158  in some operational states of the spring clamp  152 . In some embodiments, the width and the height of the opening  180  may be similar to the width and the height of the opening  164 . However, because the spring  154  is biased in the direction of D 1 , i.e., away from the cage  158 , the openings  180  and  164  are not aligned unless pressure is applied to the spring  154 . When a technician actuates the spring  154  by applying pressure to the fastener  159 , the opening  180  moves downward (i.e., in the direction opposite to D 1 ) so that the openings  180  and  164  become aligned, and an end of a wire can enter the cage  158 . The technician may then stop applying pressure to the fastener  159 , and the spring  154  clamps the wire by pressing the wire in the direction D 1  against the edge of the middle shelf  174  and, in some embodiments, the inner wall of the cover  162 . 
     Similar to the spring finger  26  discussed with reference to  FIGS. 1-4 , the spring  154  may be made of a resilient material having a memory. By contrast, the base  160  may be relatively rigid so as to display little or no deflection in response to pressure applied to the spring  154 . In other words, the positioning of each part of the base  160  relative to the opening  164  is preferably the same in all operational states of the terminal wire block  150 . 
     Once the spring clamp  152  secures the wire in a fixed position, the technician sometime may wish to also engage the screw clamp  156  to provide additional integrity and security to the contact. In this embodiment, the spring  154  includes an internally threaded opening  190  in the portion corresponding to the upper tail of the letter “G” with which the fastener  159  may mate. A sleeve or guide  192  may be rigidly secured to the spring  154  at the opening  190  to properly guide the fastener  159 . In another aspect, the sleeve  192  may help to distribute the pressure applied to the spring  154  via the fastener  159  when the spring clamp  152  is being engaged. 
     When the technician threads or otherwise tightens the fastener  159 , the loop section of the spring  154  contracts, thereby increasing the pressure the spring  154  exerts on the wire in the direction D 1 , and thus improving the integrity and security of the contact. To release the wire, the technician may loosen the fastener  159  to first disengage the screw clamp  156 , and then apply pressure to the fastener  159  to align the openings  180  and  164  until the wire can be released. 
       FIG. 8  illustrates a side view of the terminal wire block  150 . As best illustrated in this drawing, the base  160  defines two sufficiently large cavities  194  and  196  in the lower and upper sections of the base  160 , respectively, to allow the corresponding sections of the spring  154  to freely move when pressure is applied to the fastener  159 , or when the technician tightens the fastener  159 . 
     It is noted that some technicians may inadvertently release the wire held by the spring clamp  152  when operating the screw clamp  156 . In particular, the technician must apply little pressure to the fastener  159  in the direction opposite to D 1  when tightening the fastener  159 , e.g., by threading the work end of the fastener  159  in the clockwise direction if the fastener  159  is a screw, a bolt, or another type of an externally threaded fastener. 
     Now referring to  FIG. 9 , a terminal wire block  200  with a spring clamp  202 , a wire clamp  204 , and a housing  206  reduces the probability of accidental release of the wire by biasing a spring  210  of the spring clamp  202  both against an upper section of the housing  206  and against an inclined wall  212  of the housing  206 . The arrows indicating the directions D 1  and D 2  schematically illustrate the respective directions of the two biases. It is noted that the bias in the direction D 1  is largely similar to the bias of the spring  154  of  FIGS. 6-8 . It is also noted that the direction D 2  is depicted only approximately, and that the direction D 2  need not be orthogonal to D 1 . Generally speaking, D 2  may be selected so that the spring  210  exerts at least some pressure on the inclined wall  212  when pressure is applied to the spring  210  in the direction opposite to D 1 . 
     In the example embodiment illustrated in  FIG. 9 , the spring  210  is shaped as a letter “s” with another letter “s”, rotated 90 degrees, inscribed into the middle section and bent so as to align with the inclined wall  212 . In particular, a section  213  of the spring  210  may be parallel to the inclined wall  212  to provide friction between the section  213  and the inclined wall  212  when the spring  210  is compressed in the direction opposite to D 1 . The spring  210  may also include an opening  214  through which a wire may enter a cage  216  if the spring  210  is sufficiently compressed in the direction opposite to D 1  for the opening  214  to align with an opening  218  in the housing  206 . Further, a flexible bracket or mount  220  may be rigidly secured to the spring  210  below an opening  218 . The upper wall of the flexible bracket  220  in these embodiments defines the floor of the cage  216 . 
     With continued reference to  FIG. 9 , the housing  206  may include another opening  230  to accept a fastener  232  which may be an externally threaded fastener such as a screw or a bolt. In an embodiment, a head  234  of the fastener  232  is elongated to provide better guidance to the force a technician applies to the spring  210 . The fastener  232  may be coupled to the spring  210  via an internally threaded opening  236 . 
     To engage the spring clamp  202 , a technician applies pressure to the fastener  232  to align the opening  214  with the opening  218 , and pushes an end of a wire into the cage  216 . Because of the shape of the spring  210 , some of the pressure the fastener  232  communicates to the spring  210  at the opening  236  is directed at the inclined wall  212 . As a result, the technician must exert greater pressure to align the openings  214  as  218  as compared to the embodiment of  FIGS. 6-8  (assuming the springs  154  and  210  have similar composition and thickness). Moreover, the pressure applied to the fastener  232  must be sufficient to deflect or bend the upper section of the bracket  220  toward the opening  218 . In other words, the bias in the direction D 2  provides better guidance to pressure applied to the fastener  232 . Once the technician stops applying the requisite amount of pressure to the fastener  232 , the spring  210  clamps the wire between the housing  206  and the upper section of the bracket  220 . 
     To also engage the screw clamp  204 , the technician may thread the fastener  232  which may be a screw, for example. The screw clamp  204  may clamp the wire between a work end  240  of the fastener  232  and the upper section of the bracket  220 . In at least some of the embodiments, the tail of the spring  210  may also bend toward the upper section of the bracket  220  if the technician continues to thread the fastener  232  after the work end  240  reaches the upper section of the bracket  220 . Although the use of the screw clamp  204  is optional, the terminal wire block  200  may provide a secure and reliable wire contact by clamping the wire with both the spring clamp  202  and the wire clamp  204 . Similar to the terminal wire block  150 , the terminal wire block  200  releases the wire if the fastener  232  is loosened, and sufficient pressure is applied to the fastener  232  in the direction opposite to D 1 . 
     In some embodiments, the base  206  may be soldered to a circuit board. If desired, one or several contacts  244  may extend or be soldered to the lower portion of the bracket  220  to provide an easily detachable connection to a wiring board. 
     In an embodiment suitable for use with wires that carry 4-20 mA signals in a process control environment, for example, the spring  210  may be made of beryllium copper and have a thickness of approximately 0.457 mm (26 gauge). Further, the maximum stress of the spring  210  may be approximately 90% of yield. The initial preload at 1 mm nominal deflection may be 1.5 lbs, and the maximum load at full screw deflection may be 6.5 lbs. In other embodiments, it is also contemplated that stainless steel may be used to manufacture the spring  210 . Further, the composition and thickness of the spring  154  (illustrated in  FIGS. 6-8 ) may be similar to the composition and thickness of the spring  210 . 
     Now referring to  FIG. 10 , a multiple-input wire connector  300  includes two terminal wire blocks  302  and  304  identical or similar to the terminal wire block  200  disposed at the upper and lower levels of the wire connector  300 , respectively. The elevation of the terminal wire block  302  relative to the terminal wire block  304  provides convenient access to each of the terminal blocks  302  and  304 . In this embodiment, the terminal wire blocks  302  and  304  may share a common housing  310  to simplify the process of manufacturing and assembly of the wire connector  300 . Further, similar to the multiple-input wire connector  100  illustrated in  FIG. 5 , the wire connector  300  may include multiple terminal wire blocks on each of the upper and lower levels. As illustrated in  FIG. 10 , the wire connector  300  may be mountable on a circuit or wire board, for example, and may engage the corresponding electrical contacts via pairs of connectors  312  and  314 . If desired, it is possible to manufacture the wire connector  300  with a small foot print. In one embodiment, for example, the height and the length of the wire connector  300  is approximately 36 mm and 30 mm, respectively, with a thickness of each pair of terminals blocks  302  and  304  of approximately 6.35 mm. 
     From the foregoing, it will be appreciated that the terminal wire block  10 ,  150 , or  200 , as well as the multiple-input connector  100  or  300 , addresses individual preferences of technicians by providing independently operable wire clamps implementing different wire clamping techniques. When using the terminal wire block  10  or the multiple-input connector  100 , for example, a technician need not necessarily use a screwdriver or another tool or, conversely, the technician may choose not to engage the push-in contact of the spring clamp  14  if the push button  34  is hard to reach, for example. Moreover, the technician may also choose to provide additional contact integrity by securing the wire  12  using both the spring clamp  14  and the screw clamp  16 . On the other hand, the terminal wire block  150  or  200  allows a technician to engage the spring clamp  152  or  202  alone, or together with the corresponding screw clamp  156 , using a single tool such as a screwdriver. 
     While the present system and methods have been described with reference to specific examples, which are intended to be illustrative only and not to be limiting of the disclosure, it will be apparent to those of ordinary skill in the art that changes, additions and/or deletions may be made to the disclosed embodiments without departing from the spirit and scope of the disclosure.