Abstract:
A connector structure of a circuit board for a power supply apparatus includes an insulating housing, conductive terminals, and at least one supporting rods with each connected to the mounting surface of the insulating housing and having a pillared portion, a first protruding latch and a second protruding latch both extending laterally from a first location and a second location on the pillared portion of the supporting rod respectively. The thickness of a first circuit board is different from the thickness of a second circuit board, thus when a supporting rod passes through a first pinhole on the first circuit board, the first protruding latch props against a bottom of the first circuit board, and when a supporting rod passes through a second pinhole on the second circuit board, the second protruding latch props against a bottom of the second circuit board to prevent a movement of the connector respectively.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention is a CIP application of the parent application “Connector Structure for Power Supply Apparatus” bearing on the Ser. No. 10/015,345 and filed on Dec. 12, 2001. The present invention is directed to a connector structure for a power supply apparatus, and more particularly is directed to a connector structure of a circuit board for a power supply apparatus.  
         DESCRIPTION OF THE PRIOR ART  
         [0002]    The power supply apparatus is mainly designed for rectifying and converting commercially available power into direct current (DC) power to power a power-receiving device. FIG. 1( a ) and FIG. 1( b ) respectively show an exploded view and an elevation view of a conventional power supply apparatus. The conventional power supply apparatus basically consists of an upper housing  1  and a lower housing  2 . A space is defined between the upper housing  1  and the lower housing  2  for accommodating a circuit board  3  therein. A connector  4  and other necessary electronic elements  30  required by the power supply apparatus are mounted on the circuit board  3 . A first concave  11  and a second concave (not shown) are respectively provided on the front side and the rear side of the upper housing  1 . A third concave  21  and a fourth concave  22  respectively opposite to the first concave  11  and the second concave are respectively provided on the front side and the rear side of the lower housing  2 . When the upper housing  1  and the lower housing  2  are jointed together, the first concave  11  and the third concave  21  forms a rabbet for infixing the connector  4  therein to receive external AC power. The circuitry mounted on the circuit board  3  rectify the AC power into DC power and supply the rectified DC power to power-receiving appliances such as printers, radios and modems through electric wires.  
           [0003]    Referring to FIG. 2( a ) to FIG. 2( d ). The connector  4  basically includes an insulating housing  40  and two conductive terminals  42 . The conductive terminals  42  are located in the through-holes inside the housing  40  and pass through the apertures on the backside of the housing (not shown) to create pins  41 . Two supporting rods  43  are formed at the bottom  402  of the housing  40 . Both the supporting rods  43  and the housing  40  are integrally formed by plastic injection molding technique. The two sides  431  of the supporting rod  43  respectively extends downwards from the bottom  402  of the housing  40  for a distance h and stretches out transversely to form a protruding member  433  with a protruding plane  432 . The maximum transversal length d1 of the protruding member  433  is slightly larger than the width d2 of the pinhole  32 , and the length h that the supporting rod  43  extends downwards from the housing bottom  402  is slightly larger than the thickness T of the circuit board  3 . Because the supporting rod  43  is made up of a plasticity material with an inherent elasticity, the protruding member  433  can pass through the pinhole  32  of the circuit board  3  by exerting an external force thereto until the protruding plane props against the bottom of the circuit board  3 . The connector  4  can be fixed to the circuit board  3  accordingly.  
           [0004]    Referring back to FIG. 1( a ), the connector  4  and the circuit board  3  are connected in such a way that the two metal pins  41  are inserted into the corresponding pinhole  31  on the circuit board  3 . Subsequently the protruding member  433  of the supporting rod  43  passes through the pinhole  32  on the circuit board  3  and is adequately positioned. Finally the metal pins  41  are fixed to the circuit board  3  by welding technique.  
           [0005]    However, though the above-described way for fixing the connector  4  to the circuit board  3  can allow the connector  4  to be mounted on the circuit board  3  steadily, taking a circuit board with a thickness of 1.6 millimeter and a circuit board with a thickness of 1.2 millimeter as examples, two types of connectors each of which is of different extension length h for the supporting rod are required to fulfill the demands of matching with the circuit boards of different thickness. That signifies that two different molds are needed to manufacture the connector. Therefore the manufacturing cost for the connector will increase substantially and the amount of connectors of different specifications is not likely to be determined in advance, which causes a difficulty in the material management operation.  
           [0006]    Since a connector structure for holding circuit boards of different thickness is needed, an improved connector structure comprising an insulating housing, at least two conductive terminals, and at least one supporting rod was proposed in the previous application bearing on the Ser. No. 10/015,345 and filed on Dec. 12, 2001. The proposed connector structure is characterized by that the two sides of the supporting rod respectively extends downwards for a first length and a second length and stretches out to form a protruding member with a first protruding plane and a second protruding plane, wherein the first length is slightly larger than a thickness of a first circuit board and the second length is slightly larger than a thickness of a second circuit board, such that when the protruding member passes through a first pinhole on the first circuit board, the first protruding plane props against a bottom of the first circuit board, and when the protruding member passes through a second pinhole on the second circuit board, the second protruding plane props against a bottom of the second circuit board. However, the important features that the first length is larger than the second length, the thickness of the first circuit board is larger than the second circuit board, the supporting rods are in pillared shape and without any slot or aperture, and the first protruding plane and the second protruding plane are substantially perpendicular to the supporting rods are not defined clearly in the claims but are illustrated in the drawings and described in the specification of the above-mentioned previous application. Therefore, the present invention with clearly defined claims regarding the above mentioned features is proposed as a CIP application to clarify all the ambiguities in the claims of the parent application.  
           [0007]    In the invention of Bendorf et al. (U.S. Pat. No. 6,123,580), a board lock disposed within the receiving aperture of an electrical connector for holding the connector on a thinner circuit board as well as on a thicker circuit board is proposed. The board lock includes a body having a connector engaging portion and two cantilever beams extending from opposite transverse edges. The inner edges of the beams define a slot in between that extends into an enlarged aperture in the center of the body. Each of the outer edges of the beams includes a protrusion and further includes a latching portion at the leading end. By locating the two latches at slightly different distances from the bottom of the housing of the connector the board lock can accommodate tolerance variations in the thickness of the board. Certain noticeable features of Bendorf et al. are that the two cantilever beams of the board lock are going through the same pinhole of the circuit board, only the portion of one latch that is beyond the width of its protrusion is engaged with the bottom surface of a circuit board, and the other latch is either remained in the pinhole for the thicker circuit board case or is spaced from the circuit board for the thinner circuit board case. But due to the following unique features of the present invention that the two supporting rods are in pillared shape without any slot or aperture employed and are aligned in parallel, each of the two supporting rods goes through a different pinholes respectively, the two first (second) protruding latches with one protruding latch from each supporting rod are both propped against the bottom surface of the circuit board and are substantially perpendicular to the supporting rods, and one first (second) protruding latch is stretched to the right and the other first (second) protruding latch is stretched to the left respectively, the connector could be hold to the circuit board more firmly than in the case of Bendorf et al. where only one out of the two latches is engaged with the bottom surface of the circuit board.  
           [0008]    In Bendorf et al., if the circuit board is flexed downward a sufficient amount, the two cantilever beams will be pushed inwardly against the slot to become more closely. The two cantilever beams are integrally formed with the housing of the board lock which is disposed within the receiving aperture of the connector. If there is a space squashed out of the slot in between the two cantilever beams, then that will result a upward movement of the connector. One of the two cantilever beams is only having either a protrusion or a latch extended outwardly against the wall of the pinhole but not engaged with the bottom surface of the circuit board. The flexed circuit board will lean to the cantilever beam with the latch either in or away from the pinhole, and the connector will be moved upwardly a little bit while the cantilever beam with the latch either in or away from the pinhole is slid upwardly along the wall of the pinhole since only the other latch is engaged with the bottom surface of the circuit board. Therefore, a space squashed out of the slot in between the two cantilever beams will cause the board lock to slide upwardly along the pinhole and lean to the outer edge of one cantilever beam with a maximum distance counting from the protrusion to the latch of the same cantilever beam if the protrusion is extended outwardly against the wall of the pinhole, and with a maximum distance up to the space squashed out of the slot if the latch is extended outwardly against the wall of the pinhole. Due to the unique features of the present invention mentioned above, the two supporting rods will be firmly positioned and connected to the connector by the two first (second) protruding latches which are firmly engaged with the bottom surface of the connector and there is no possibility that the connector could be moved upwardly. Therefore, there is no such a problem in the present invention that the connector might be moved upwardly by flexed a sufficient amount of the circuit board.  
           [0009]    In Bendorf et al., the two cantilever beams are integrally formed with the housing of the board lock which is disposed within the receiving aperture of the connector. Thus, the board lock and the connector might be separated if an unexpected force is employed to pull the connector outwardly by accident before the welding process. But in the present invention, the two supporting rods are integrally formed with the insulating house of the connector and there is no separable component like the block lock of the Bendorf et al. in the connector. Therefore, there is no such a problem in the present invention that a component might be pulled out of the connector by accident.  
           [0010]    A board lock with a high retention force typically requires a high insertion force, which makes it harder to mount the connector to the board. In Bendorf et al., it is proclaimed that less insertion force is required when the connector is mounted to the circuit board due to an enlarged aperture in the board lock is employed causing the lengths of the cantilever beams to be extended, and the supporting rods to be more flexible than those of the prior arts. But the slot and aperture in between the two cantilever beams are still employed to applied a retention force to the wall of a pinhole on the circuit board in Bendorf et al., the dilemma of high retention force versus high insertion force still remains. Due to the following reasons regarding the present invention that the supporting rods are in pillared shape and there is no slot or aperture employed, the maximum transversal length of each protruding latch is just slightly larger than the width of each pinhole, and the elasticity of the protruding latchs made of plastic material, the insertion force needed to push each of the supporting rod through each of the pinhole is much less than the insertion force needed in Bendorf et al. where a slot and an aperture in between the two cantilever beams are employed to produce the retention force.  
           [0011]    Therefore, the purpose of the present invention is to develop a connector structure of a circuit board for a power supply apparatus to deal with the above situations encountered in the prior arts.  
         SUMMARY OF THE INVENTION  
         [0012]    An object of the present invention is the provision of a connector structure for a power supply apparatus which can be applied for circuit boards of different thickness and can be fixed to the circuit board steadily.  
           [0013]    Another object of the present invention is the provision of a connector structure for a power supply apparatus for reducing the manufacturing cost of the connector.  
           [0014]    A first aspect of the present invention is a presentation of a connector for a power supply apparatus, including: an insulating housing having a mounting surface; at least two conductive terminals; and a supporting rod connected to the mounting surface of the insulating housing, further including: a pillared portion; a first protruding latch connected to the pillared portion and extending laterally from a first location on the pillared portion; and a second protruding latch connected to the pillared portion and extending laterally from a second location on the pillared portion, wherein, a thickness of first circuit board is different from a thickness of the second circuit board, the first location is one of those closer to and further away from the mounting surface than the second location and the first protruding latch and the second protruding latch are vertically displaced, such that when the supporting rod passes through a first pinhole on the first circuit board, the first protruding latch props against the bottom of the first circuit board, and when the supporting rod passes through a second pinhole on the second circuit board, the second protruding latch props against the bottom of the second circuit board to prevent a movement of the connector respectively.  
           [0015]    In accordance with the connector as described hereinto, the supporting rod is integrally formed with the mounting surface of the insulating housing.  
           [0016]    In accordance with the connector as described hereinto, the first protruding latch is integrally formed with the pillared portion of the supporting rod.  
           [0017]    In accordance with the connector as described hereinto, the second protruding latch is integrally formed with the pillared portion of the supporting rod.  
           [0018]    In accordance with the connector as described hereinto, wherein the projection of the protruding direction of the first protruding latch of the supporting rod and the projection of the protruding direction of the second protruding latch of the supporting rod have an angle of 180 degrees.  
           [0019]    A second aspect of the present invention is a presentation of a connector for a power supply apparatus, including: an insulating housing having a mounting surface; at least two conductive terminals; and two supporting rods having a first supporting rod and a second supporting rod both connected to the mounting surface of the insulating housing and aligned in parallel, each further including: a pillared portion; a first protruding latch connected to the pillared portion and extending laterally from a first location on the pillared portion; and a second protruding latch connected to the pillared portion and extending laterally from a second location on the pillared portion, wherein, a thickness of first circuit board is different from a thickness of the second circuit board, the first location is one of those closer to and further away from the mounting surface than the second location, the first protruding latch and the second protruding latch of one of the first supporting rod and the second supporting rod are vertically displaced respectively, and the first protruding latches of the first supporting rod and the second supporting rod, and the second protruding latches of the first supporting rod and the second supporting rod are horizontally linearly displaced respectively, such that when the first supporting rod passes through a first pinhole on the first circuit board and the second supporting rod passes through a second pinhole on the first circuit board, the first protruding latches of the first and second supporting rods prop against the bottom of the first circuit board, and when the first supporting rod passes through a first pinhole on the second circuit board and the second supporting rod passes through a second pinhole on the second circuit board, the second protruding latches of the first and second supporting rods prop against the bottom of the second circuit board to prevent a movement of the connector respectively.  
           [0020]    In accordance with the connector as described hereinto, the supporting rod is integrally formed with the mounting surface of the insulating housing.  
           [0021]    In accordance with the connector as described hereinto, each of the first protruding latches is integrally formed with each of the pillared portions of the supporting rods.  
           [0022]    In accordance with the connector as described hereinto, each of the second protruding latches is integrally formed with each of the pillared portions of the supporting rods.  
           [0023]    In accordance with the connector as described hereinto, the projection of the protruding direction of the first protruding latch of the first supporting rod and the projection of the protruding direction of the first protruding latch of the second supporting rod have a angle of 180 degrees, and the projection of the protruding direction of the second protruding latch of the first supporting rod and the projection of the protruding direction of the second protruding latch of the second supporting rod have the angle of 180 degrees.  
           [0024]    Now the foregoing and other features and advantages of the present invention will be more clearly understood through the following descriptions with reference to the accompanying drawings, in which: 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]    [0025]FIG. 1( a ) is an exploded view showing a conventional power supply apparatus;  
         [0026]    [0026]FIG. 1( b ) is an elevation view showing a conventional power supply apparatus;  
         [0027]    [0027]FIG. 2( a ) is a perspective view of a connector for a power supply apparatus of the prior art;  
         [0028]    [0028]FIG. 2( b ) is a backside view of a connector for a power supply apparatus of the prior art;  
         [0029]    [0029]FIG. 2( c ) is a schematic chart illustrating how the supporting rod of the connector is inserted into the pinhole on the circuit board according to the prior art;  
         [0030]    [0030]FIG. 2( d ) is a schematic chart illustrating how the supporting rod of the connector is positioned onto the circuit board according to the prior art;  
         [0031]    [0031]FIG. 3( a ) is a schematic diagram illustrating how the supporting rod of the connector is inserted into a pinhole on a first circuit board of a thickness T 1  according to the present invention;  
         [0032]    [0032]FIG. 3( b ) is a schematic diagram illustrating how the supporting rod of the connector is positioned onto a first circuit board of a thickness T 1  according to the present invention;  
         [0033]    [0033]FIG. 3( c ) is a schematic diagram illustrating how the supporting rod of the connector is inserted into a pinhole on a second circuit board of a thickness T 2  according to the present invention;  
         [0034]    [0034]FIG. 3( d ) is a schematic diagram illustrating how the supporting rod of the connector is positioned onto a second circuit board of a thickness T 2  according to the present invention;  
         [0035]    FIG. 4 ( a ) is a schematic diagram showing the protruding directions of the first and second protruding latches of the first and second supporting rods respectively;  
         [0036]    [0036]FIG. 4( b ) is a schematic diagram showing a case with the two angles between the projections of the protruding directions of the first protruding latches of the first and second supporting rods and between the projections of the second protruding latches of the first and second supporting rods respectively upon the mounting surface both being 180 degrees; and  
         [0037]    [0037]FIG. 4( c ) is a schematic diagram showing a case with the four angles between the projections of the protruding directions of the first protruding latch and second protruding latch of one of the first and second supporting rods and one of first and second protruding latches of the first supporting rod and second supporting rod respectively upon the mounting surface. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0038]    An exemplary embodiment of the present invention now will be fully described with reference to the following preferred embodiment. It is to be emphasized that the following descriptions of embodiments and examples of the present invention is only illustrative, and it is not intended to be exhaustive or not to be limited to the precise form disclosed.  
         [0039]    [0039]FIG. 3( a ) and FIG. 3( b ) are schematic diagrams respectively illustrating how the supporting rod of the connector is inserted into a pinhole on a first circuit board  6  of a thickness T 1  according to the present invention and how the supporting rod of the connector is positioned onto the first circuit board  6  of a thickness T 1  according to the present invention. FIG. 3( c ) and FIG. 3( d ) are schematic diagrams respectively illustrating how the supporting rod of the connector is inserted into a pinhole on a second circuit board  7  of a thickness T 2  according to the present invention and how the supporting rod of the connector is positioned onto the second circuit board  7  of a thickness T 2  according to the present invention. A first supporting rod  53  and a second supporting rod  54  are formed at the mounting surface  502  of the housing  50  of the connector  5 . The first supporting rod  53  and the second supporting rod  54  are integrally formed with the housing  5  with plastic injection molding technique. A pillared portion  530  of the first supporting rod  53  having two sides  531  and  532  respectively extends downwards for a first length h 1  and a second length h 2 , and then stretches out to form a protruding member  535  with a first protruding latch  533  and a second protruding latch  534  both extending laterally from a first location  536  and a second location  537  on the first supporting rod  53 . By the same token, a pillared portion  540  of the second supporting rod  54  having two sides  541  and  542  respectively extends downwards for a first length h 1  and a second length h 2 , and then stretches out to form a protruding member  545  with a first protruding latch  543  and a second protruding latch  544  both extending laterally from a first location  546  and a second location  547  on the second supporting rod  54 .  
         [0040]    Please refer to FIG. 4( a ), the first supporting rod  53  and the second supporting rod  54  are aligned in parallel, the first protruding latch  533  of the first supporting rod  53  and the first protruding latch  543  of the second supporting rod  54  are stretched in opposite directions, and the second protruding latch  534  of the first supporting rod  53  and the second protruding latch  544  of the second supporting rod  54  are stretched in opposite directions respectively. Which means the angle between the projection of a protruding direction  5331  of the first protruding latch  533  and the projection of a protruding direction  5431  of the second protruding latch  543  is 180 degrees, and the angle between the projection of a protruding direction  5341  of the first protruding latch  534  and the projection of a protruding direction  5441  of the second protruding latch  544  is 180 degrees too. The protruding direction  5331  is a central normal pointing outwardly away from the central axis  538  and passing through a central position  5332  of the outer edge  5333 , and is horizontally aligned with the surface of the protruding plane  5334  of the first supporting rod  53 . The protruding direction  5341  is a central normal pointing outwardly away from the central axis  538  and passing through a central position  5342  of the outer edge  5343 , and is horizontally aligned with the surface of the protruding plane  5344  of the first supporting rod  53 . The protruding direction  5431  is a central normal pointing outwardly away from the central axis  539  and passing through a central position  5432  of the outer edge  5433 , and is horizontally aligned with the surface of the protruding plane  5434  of the second supporting rod  54 . The protruding direction  5441  is a central normal pointing outwardly away from the central axis  539  and passing through a central position  5442  of the outer edge  5443 , and is horizontally aligned with the surface of the protruding plane  5444  of the second supporting rod  54 . Please refer to FIG. 4( b ), the projection of a protruding direction  5331  passing through a central position  5332  using the mounting surface  502  as the projecting surface is pointing outwardly away from a point  5381  located both on the mounting surface  502  and on the central axes  538  as a reference origin, and the projection of a protruding direction  5431  passing through a central position  5432  using the mounting surface  502  as the projecting surface is pointing outwardly away from a point  5481  located both on the mounting surface  502  and on the central axes  548  as a reference origin. The angle between the projection of the protruding direction  5331  and the projection of the protruding direction  5431  is 180 degrees. The projection of a protruding direction  5341  passing through a central position  5342  using the mounting surface  502  as the projecting surface is pointing outwardly away from a point  5381  located both on the mounting surface  502  and on the central axes  538  as a reference origin, and the projection of a protruding direction  5441  passing through a central position  5442  using the mounting surface  502  as the projecting surface is pointing outwardly away from a point  5481  located both on the mounting surface  502  and on the central axes  548  as a reference origin. The angle between the projection of the protruding direction  5341  and the projection of the protruding direction  5441  is 180 degrees too.  
         [0041]    Please refer to FIG. 4( c ), a second preferred embodiment of the present invention could have a cylindrical shaped first supporting rod  53  having a first latch  533  and a second latch  534  with a angle θ 112  (30 degrees) between the projections of the protruding directions  5331  and  5341  onto the mounting surface  502  using the point  5381  as the reference origin, and a cylindrical shaped second supporting rod  54  having a first latch  543  and a second latch  544  with a angle θ 212  (30 degrees) between the projections of the protruding directions  5431  and  5441  onto the mounting surface  502  using the point  5381  as the reference origin. By the same token, a angle θ 11  between the projections of the protruding directions  5331  and  5431  onto the mounting surface  502  using the points  5381  and  5481  as the reference origins respectively is 180 degrees. A angle θ22 between the projections of the protruding directions  5341  and  5441  onto the mounting surface  502  using the points  5381  and  5481  as the reference origins respectively is 180 degrees too. The angles θ 112 , θ 212 , θ 11 , and θ 22  each could have an included angle except being 0 respectively so as to fix the connector  50  to the circuit board properly and to prevent a movement of the connector  50  from the circuit board.  
         [0042]    Please refer to FIG. 3( a ) and FIG. 4( a ) again. The first protruding latch  533  and the second protruding latch  534  of the first supporting rod  53 , the first protruding latch  543  and the second protruding latch  544  of the second supporting rod  54  are vertically displaced respectively. Which means the first protruding latch  533  and the second protruding latch  534  of the first supporting rod  53 , the first protruding latch  543  and the second protruding latch  544  of the second supporting rod  54  are not vertically aligned respectively. The first protruding latches ( 533  and  543 ) of the first supporting rod  53  and the second supporting rod  54 , and the second protruding latches ( 534  and  544 ) of the first supporting rod  53  and the second supporting rod  54  are horizontally linearly displaced respectively. Which means the first protruding latches ( 533  and  543 ) of the first supporting rod  53  and the second supporting rod  54 , and the second protruding latches ( 534  and  544 ) of the first supporting rod  53  and the second supporting rod  54  are not horizontally linearly aligned respectively.  
         [0043]    In the present embodiment, the first length h 1  is slightly larger than the thickness T 1  of the first circuit board  6 , the second length h 2  is slightly larger than the thickness T 2  of the second circuit board  7 , and the first length h 1  is larger than the second length h 2 . More preferably, the thickness T 1  of the first circuit board  6  is 1.6 millimeter, and the thickness T 2  of the second circuit board  7  is 1.2 millimeter.  
         [0044]    Certainly, the position and dimension of the pinhole  62  on the first circuit board  6  and the pinhole  72  on the second circuit board  7  has to be dynamically modulated. The maximum transversal length W 1  of the protruding member  535  is slightly larger than the width W 2  of the pinhole  62  on the first circuit board  6  and the width W 3  of the pinhole  72  on the second circuit board  7 . In FIG. 3( a ) and FIG. 3( b ), by exerting an external force thereto the protruding member  535  can pass through the pinhole  62  on the first circuit board  6  due to its elasticity, such that the first protruding latch  533  can prop against the bottom of the first circuit board  6  and the connector  5  can be fixed to the first circuit board  6 . By the same token, in FIG. 3( c ) and FIG. 3( d ), by exerting an external force thereto the protruding member  535  can pass through the pinhole  72  on the second circuit board  7  due to its elasticity, such that the second protruding latch  534  can prop against the bottom of the second circuit board  7  and the connector  5  can be fixed to the second circuit board  7 .  
         [0045]    Certainly, the supporting rod of the connector of the present invention can not only fit for the connector with two conductive terminals, but also fit for the connector with three conductive terminals (with a conductive terminal is designated as a ground terminal).  
         [0046]    Of course, the amount of the supporting rod of the connector according to the present invention can be one or more than two, wherein two is the most preferable.  
         [0047]    In conclusion, the connector of the present invention adopts a particular supporting rod arrangement, and thereby the connector of the present invention can be positioned and fixed onto the circuit boards of different thickness. As a result, only a connector is required for two circuit boards each of which is of a different thickness. By way of standardizing the supporting rod arrangement, the objectives of reducing manufacturing cost of the connector and improving the efficiency of material management operation can be achieved with ease.  
         [0048]    While the invention has been described in terms of what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention need not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures. Therefore, the above description and illustration should not be taken as limiting the scope of the present invention which is defined by the appended claims.