Abstract:
An insulative circuit board receives a forged terminal and a simplified terminal plate, inserted through a through hole and guided by insertion slots, to form a complete terminal connector. The terminal plate firmly fixes to the insulative circuit board by locking into integrally formed locking steps. The terminal is retained by the snap-in terminal plate and preventive elements formed integrally with the circuit board. Preventive elements prevent unexpected disassembly when the terminal and the terminal plate loose threaded engagement and eliminates the need for after-integration processing. A guiding element, integral with the terminal, guides the terminal into threaded engagement with the terminal plate. The guiding element also prevents damage to a terminal plate screw hole and speeds assembly.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a terminal connector for input and output of electric signals, particularly in audio and video equipment systems.  
           [0003]    2. Description of the Related Art  
           [0004]    Referring to FIG. 4, a conventional terminal connector, shown generally at  100 ′, includes an electrically conductive terminal plate  14  mounted on an insulative circuit board  10 . A terminal  15  is secured to insulative circuit board  10  by a screw portion  17  threaded through a screw hole  16  in terminal plate  14 . A knob  19 ′, affixed projecting away from insulative circuit board  10  enables screwing and unscrewing screw portion  17  for making electrical connection, as will be explained. Conventional terminal connectors of this type generally have a four-gang or eight-gang configuration.  
           [0005]    Circuit board  10  includes four cylindrical portions  11  (two not shown). Cylindrical portions  11  are integrally formed on a first surface of circuit board  10  and surround a part of terminals  15  near the first surface of circuit board  10 . Cylindrical portions  11  help avoid lead wire shorts and reduce the chance of electrical contact with a person or an object. Cylindrical portions  11  each have at least one lead wire insertion notch  12  in an outer periphery.  
           [0006]    A through hole  13  accommodates adjustable screw portion  17  of terminal  15 . Screw portion  17  is centered in cylindrical portion  11 . Around through hole  13 , a plurality of insertion holes  20  permit insertion of one or more press-in lock pieces  21  and a terminal portion  22  of terminal plate  14  into selected insertion holes  20  to fix terminal plate firmly to insulative circuit board  10 . Terminal portions  22  have connective ends formed opposite terminal plate  14  for connecting to a printed circuit board  34 .  
           [0007]    During assembly, the extremities of terminal portions  22  of terminal plates  14  are inserted into cylindrical portions  11  from above and slipped partially into insertion holes  20 . Further insertion of terminal portions  22  requires rotating terminal portion  22  (counter clock wise to the plane of the page) to allow bends  33  to freely pass through cylindrical portions  11  and protrude from a second surface of circuit board  10 . As terminal portions  22  protrude through the second surface of the insulative circuit board  10 , press-in lock pieces  21 , of terminal plates  14 , are pressed into the remaining insertion holes  20  for fixture. After assembly, a bottom surface of terminal plate  14  rests directly against a top surface of circuit board  10 .  
           [0008]    After the integration of terminal plates  14  and terminal portions  22 , terminals  15  are threaded into terminal plates  14 . Screw portions  17  are screwed into screw holes  16  formed in terminal plate  14 . When each screw portion  17  is tightened, a collar  18  of terminal  15  contacts terminal plate  14 , and an end portion of screw portion  17  protrudes below the second surface of insulative circuit board  10 . After tightening, the end portion of screw portion  17  is mechanically flattened to form a preventive bulged portion  31  and disrupt a continuous helical thread formed on screw portion  17 . Preventive bulged portion  31  prevents terminal  15  from disengaging screw hole  16  or from being lost during later adjustment.  
           [0009]    Once terminal plates  14  and terminals  15  are connected to circuit board  10 , knobs  19 ′ are loosened sufficiently to allow insertion of at least one lead wire  32  through insertion notches  12 . When screw portion  17  of each terminal  15  is tightened toward screw hole  16  in terminal plate  14 , a bottom surface of collar  18  and a top surface of terminal plate  14  sandwich lead wire  32  for electrical contact. A banana plug (not shown) may be inserted into a terminal body  59 ′, contained within terminal  15 , having a plug insertion opening  26  and a plug connection portion  23 , for electrical connection. More than one lead wire may be captured this way, and connected to a connector inserted into plug connection portion  23  and/or terminal portion  22 .  
           [0010]    Referring additionally to FIGS. 5 and 6, insertion holes  20  permit insertion of one or more press-in lock pieces  21  and terminal portions  22  of terminal plate  14  to firmly fix terminal plate  14  to insulative circuit board  10 . In FIG. 5, bulged portions  31  expand beyond an outside diameter of screw portion  17 , thus preventing disengagement. In FIG. 6, terminal portions  22  may be of different lengths and each respective bends  33  of different curvature radius.  
           [0011]    Conventional terminal connectors create several manufacturing difficulties. First, it is difficult to automate the step of integrating terminal plate  14 , with press-in lock pieces and terminal portions  22 , into insulative circuit board  10 . The extremities of terminal portions  22  require insertion in conformity with the curves on bends  33  from above the cylindrical portion  11 . Additionally, printed circuit board  34  may have terminal plates  14  with different length terminal portions  22 , depending upon production requirements. This difference in length makes automated assembly difficult.  
           [0012]    Second, the flattening step forming bulged portions  31 , described above, needs to be performed after terminal plates  14  and terminals  15  are installed into insulative circuit board  10 . As a result, performing the flattening step, during sub-assembly of terminal  15 , is inconvenient and increases manufacturing time and cost.  
           [0013]    Third, during the assembly of conventional terminal connectors  100 ′ in general and during the flattening step of bulged portions  31  specifically, damage can occur to exposed terminal portions  22 . As a result, manufacturing waste and costs are increased.  
         OBJECTS AND SUMMARY OF THE INVENTION  
         [0014]    It is an object of the present invention to provide a terminal connector where automated assembly of multiple terminal plates into an insulative circuit board is easy.  
           [0015]    It is another object of the present invention to provide a terminal connector which eliminates the need for an after-assembly flattening step while providing means for preventing the terminals from falling off or disconnecting from the terminal plates.  
           [0016]    It is another object of the present invention to provide a terminal connector having an improved assembly time and a lower defect rate.  
           [0017]    It is another object of the present invention to provide a terminal connector with reduced size and smaller footprint.  
           [0018]    An insulative circuit board receives a forged terminal and a simplified terminal plate inserted through a through hole and guided by insertion slots, to form a terminal connector. The terminal plate firmly fixes to the insulative circuit board by locking into integrally formed locking steps. The terminal is retained by the snap-in terminal plate and preventive means formed integrally with the circuit board. Preventive means prevents unexpected disassembly when the terminal and the terminal plate lose threaded engagement and eliminates the need for after-integration processing. A guiding means, formed integrally with the terminal, guides the terminal into threaded engagement with the terminal plate when the terminal and the terminal plate lose threaded contact. Guiding means also prevents damage to a terminal plate screw hole and speeds assembly.  
           [0019]    According to an embodiment of the present invention there is provided, a terminal connector comprising: a circuit board having a top and bottom face, a terminal plate attached to the circuit board, a terminal having a screw portion engaged in a screw hole formed in the terminal plate, the circuit board having a through hole, into which the terminal is inserted from the bottom face, to which the terminal plate is attached as well, and means for preventing the terminal from separating from the terminal plate when the screw portion of the terminal and the screw hole in the terminal plate lose threaded engagement.  
           [0020]    According to another embodiment of the present invention there is provided a terminal connector with preventive means further comprising: a preventive lock portion extended inward from a cylindrical portion, and a preventive lock retention portion extended outward from the terminal.  
           [0021]    According to another embodiment of the present invention there is provided a terminal connector further comprising: an insertion slot provided in a bottom surface of said circuit board to accommodate a bent portion of the terminal plate, and a lock tab integral with the bent piece for locking with a lock step provided in the insertion slot, the terminal plate attached to the insulative circuit board by inserting a bent piece of the terminal plate into the insertion slot provided on the bottom surface of the insulative circuit board so that the lock tab is locked into a lock step provided in the insertion slot.  
           [0022]    According to another embodiment of the present invention there is provided a terminal comprising: a screw portion, a minor diameter portion having a diameter smaller than that of said screw portion, a collar, a plug connection portion, and a knob having a plug insertion opening, the screw portion and the minor diameter portion being extended toward one end away from the collar at the center, the plug connection portion extended toward the other end away from the collar, the outer periphery of the plug connection portion being covered with the knob, and the minor diameter portion fitting in the screw hole when the screw portion of said terminal and said screw hole in said terminal plate threadably disengage with each other and the terminal is retained by said coming-off preventive means, the means composed of a coming-off preventive lock portion extended inward from a cylindrical portion and a coming-off preventive lock portion extended outward from the terminal.  
           [0023]    The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, where like reference numerals designate the same elements.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]    [0024]FIG. 1 is a sectional view along line A-A of FIG. 3, showing an embodiment of the terminal connector.  
         [0025]    [0025]FIG. 2 is a perspective view showing an embodiment of the terminal plate used in the terminal connector according to the present embodiment.  
         [0026]    [0026]FIG. 3 is a bottom view showing an embodiment of a terminal connector where the upper right and lower left through holes each contain a terminal plate and terminal while the upper left and lower right through holes are empty.  
         [0027]    [0027]FIG. 4 is a sectional view along line B-B of FIG. 5, showing a conventional terminal connector.  
         [0028]    [0028]FIG. 5 is a bottom view showing the conventional terminal connector of FIG. 4.  
         [0029]    [0029]FIG. 6 is a perspective view of a conventional terminal plate  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0030]    Referring to FIG. 1, a terminal connector, shown generally at  100 , includes an electrically conductive terminal plate  14  mounted to an insulative circuit board  10 . A terminal  15  is secured to insulative circuit board  10  by a screw portion  17  threaded into a screw hole  16  in terminal plate  14 . A knob  19 , fixed projecting away from terminal  15  enables screwing and unscrewing of screw portion  17  for making electrical connection, as will be explained.  
         [0031]    A cylindrical portion  11 , surrounding a part of terminal  15  near a first surface of insulative circuit board  10 , helps avoid lead wire shorts and reduces the chance of electrical contact with a person or an object. Cylindrical portion  11  is formed cylindrically about a center axis and has at least one wire insertion notch  12  in its outer periphery. Cylindrical portion  11  includes lock portion  38  protruding from an upper edge of cylindrical portion  11  and facing the central axis. Lock portions  38 , combined with retention portions  39  (later described) constitute a preventive means, as will be explained. In this embodiment, insulative circuit board  10  has four cylindrical portions  11  formed on the first surface.  
         [0032]    Each terminal  15  comprises knob  19  surrounding a terminal body  59 . Knob  19  protrudes away from the first surface and is generally cylindrical in shape. A fit hole  25  contains plug connection portion  23 , and passes through the center of knob  19 . A plug insertion opening  26 , having a diameter greater than that of fit hole  25 , is formed at the top of fit hole  25 . A circular recess at the bottom of fit hole  25  engages a collar  18 . Knob  19  is made from an electrically insulating material such as resin.  
         [0033]    The electrically conductive terminal body  59  is an integrally formed element with plug connection portion  23  at a first end, and a minor diameter portion  42  at a second end. Terminal body  59  is integrally formed from by a cold forging process or the like. Plug connection portion  23  is suitable for accepting the insertion of a conventional banana tip, a wire end, or other conductor. Collar  18  is disposed at a first intermediate location and contacts plug connection portion  23 . A screw portion  17  is disposed at a second intermediate location and contacts minor diameter portion  42 .  
         [0034]    Plug connection portion  23 , collar  18 , screw portion  17 , and minor diameter portion  42  all have circular shapes about a common axis. That is, plug connection portion  23  has a cylindrical shape, collar  18  has a disk-like shape, screw portion  17  has a cylindrical-column shape, and minor diameter portion  42  has a cylindrical-column shape. Screw portion  17  contains a continuous helical thread having a minor diameter measured from a central axis of screw portion  17 . Minor diameter portion  42  has a diameter, measured from the same central axis, less than the minor diameter of screw portion  17 . Minor diameter portion  42  serves as a guiding means later described.  
         [0035]    Knob  19  and terminal body  59  are fixed to each other by both the engagement of collar  18  and the swaging of a top rim of plug connection portion  23  to form a complete terminal  15 . This engagement prevents terminal body  59  and knob  19  from rotating respective to each other and from losing contact with each other as terminal  15  adjusts.  
         [0036]    Knob  19 , on terminal  15 , has integral circular retention portions  39 , formed around an exterior circumference and projecting away from a central axis. Knob  19  has a diameter, relative to the central axis, smaller than that of lock portions  38  formed on cylindrical portion  11  so as to allow adjustment of terminal  15  within cylindrical portion  11 .  
         [0037]    The inner diameter of cylindrical portion  11 , relative to the central axis of terminal  15 , is greater than that of retention portions  39  to allow insertion of terminal  15  from a second surface of circuit board  10 . However, the inner diameter of lock portions  38  is less than the outer diameter of retention portions  39  so as to prevent free passage of terminal  15  from the second surface of circuit board  10  through cylindrical portion  11  to the first surface of circuit board  10 . Together, lock portions  38  of cylindrical portion  11 , and retention portions  39  of knob  19 , retain terminal  15 .  
         [0038]    Formed on the second surface of circuit board  10  are through holes  43 . Through holes  43  have a diameter larger than the inner diameter of cylindrical portion  11 , but smaller than the outer diameter of cylindrical portion  11 , thus integrally forming step  44 . Through holes  43  pierce the first surface of insulative circuit board  10  and accommodate terminal plate  14 .  
         [0039]    Also formed around through hole  43 , on the second surface of circuit board  10 , is a plurality of integral insertion slots  40  with lock steps  41  for receiving and guiding terminal projections  22  of terminal plate  14 . Lock steps  41  are formed about a central axis of through hole  43  perpendicular to terminal portions  22  of terminal plate  14 .  
         [0040]    As additionally shown in FIG. 2, each terminal plate  14 , consisting of an electrically conductive material, is formed as a disk portion  30  having a central axis and a bulged contact surface portion  37  surrounding a central cylindrical threaded screw hole  16 . Screw hole  16  enables threaded electrical contact between terminal  15  with screw portion  17  and terminal plate  14 . At opposite sides of terminal plate  14 , with disk portion  30 , a pair of bent pieces  35  extend away from contact surface portion  37  each having a pair of erect lock tabs  36 . At least one of the bent pieces  35  is formed and extended along a terminal portion  22  having a distal end. Terminal portions  22  may be of variable lengths depending upon manufacturing demands.  
         [0041]    Additionally referring to FIG. 3, insulative circuit board  10  has four through holes  43  each having steps  44  and insertion slots  40  with lock steps  41 . Here, relative to the plane of the page, the top right and bottom left through holes  43  contain terminal plates  14  with terminals  15 . Bent pieces  35  of terminal plate  14  are retained between insertion slots  40  with lock steps  41  by lock tabs  36  projecting into lock steps  41 . As a result, disk portions  30  of terminals  14  firmly abut steps  44  in through holes  43 . Thus, terminal plates  14  are affixed to circuit board  10  and resists separation. In this embodiment, relative to the plane of the page, the top right and bottom right through holes  43  do not contain terminal plates  14  nor terminals  15 .  
         [0042]    During assembly of terminal connector  100 , circuit board  10  is inverted so that the second side faces upward towards an operator and terminals  15 , with knobs  19  and terminal bodies  59 , are inverted and inserted into through holes  43 . During insertion of terminals  15  into through holes  43 , knobs  19  with annular retention portions  39 , project into cylindrical portions  11  and contact annular lock portions  38 .  
         [0043]    Next during assembly, terminal plate  14 , with bent pieces  35 , is inverted and aligned with insertion slots  40 , formed on circuit board  10 . During alignment, a central axis of screw hole  16  on terminal  14  and a central axis of minor diameter portion  42  of terminal  15  are aligned. Since minor diameter portion  42  has a diameter smaller than that of screw hole  16 , minor diameter portion  42  functions to align and guide terminal plate  14  during assembly. Terminal plate  14  with disk portion  30  is inserted through insertion slots  40  and pressed downward into through hole  43  towards the first surface of circuit board  10 . Pressing continues until disk portion  30  contacts step  44  and lock tabs  36  are released from elastic compression and extended into lock steps  41 , thereby fixing terminal plates  14  into circuit board  10 .  
         [0044]    Simultaneously, screw hole  16  of terminal plate  14  surrounds minor diameter portion  42  of terminal  15 , thereby retaining terminal  15  between contact surface portion  37  of terminal plate  14  and lock portion  38  of cylindrical portions  11  thus enabling both guiding means for screw portion  17  and preventive means for terminal  15 .  
         [0045]    After insertion of terminal plates  14 , circuit board  10  is inverted so that the first face is facing upward and that terminals  15 , with minor diameter portions  42 , are guided by into aligned contact with screw hole  16 . Knobs  19  are rotated so that threaded portions  17  of terminals  15  engage screw holes  16  of terminal plates  14 , and thereby complete assembly of terminal connector  100 .  
         [0046]    Depending upon manufacturing requirements, extended terminal portions  22  of terminal plate  14  may engage more than one adjacent insertion slot  40  around adjacent through holes  43  so as to securely protrude a distal end to an edge of circuit board  10 .  
         [0047]    After assembly of terminal connector  100 , banana clips, wire leads or other contacts may be inserted in plug insertion opening  26  of terminal  15  or through insertion notches  12  of cylindrical portion  11 , to enable electrical contact to terminal projections  22  of terminal plate  14 .  
         [0048]    The present embodiment offers several positive points.  
         [0049]    First, even where knobs  19  are reversed until screw portions  17  and screw holes  16  threadably disengage, minor diameter portions  42  simply provide free rotation while lock portions  38  and retention portions  39  contact each other and prevent terminal  15  from being removed from cylindrical portion  11 .  
         [0050]    Second, while minor diameter portions  42  may turn freely in screw holes  16 , minor diameter portions  42  also maintains insertion in screw holes  16 . Therefore, when knobs  19  are tightened again, minor diameter portions  42  guided threaded portions of terminals  15  into screw holes  16  for quick and smooth threaded engagement.  
         [0051]    Third, in the present embodiment, terminals  15  are inserted from the second surface of circuit board  10  into through holes  43  and terminal plates  14  are attached thereto. This eliminates the need for the conventional manufacturing step of flattening the extremities of screw portions  17  of terminals  15  to form preventive bulged portions  31 . This saves manufacturing time and manufacturing resources.  
         [0052]    Fourth, since terminals  15  and terminal plates  14  are simply inserted in insulative circuit board  10 , automated assembly is more easily achieved saving manufacturing costs.  
         [0053]    Fifth, preventive means consisting of lock portions  38  integral with cylindrical portions  11  and retention portions  39  protruded from terminals  15 , facilitate the fabrication of insulative circuit board  10  by preventing unplanned disassembly and lost parts.  
         [0054]    Sixth, integral bent pieces  35  and lock tabs  36  of terminal plate  14  are inserted in insertion slots  40 . Accordingly, the integration of terminal plates  14  to insulative circuit board  10  requires the pressing of terminal plate  14  into insertion slots  40  on insulative circuit board  10  to thereby engage lock tabs  36  into lock steps  41 . As a result, assembly is easily automated.  
         [0055]    Seventh, after assembly, minor diameter portion  42 , within screw hole  16  guides screw portion  17  of terminal  15  into threaded engagement with screw hole  16 . This prevents misalignment of threaded portion  17  with screw hole  16  eliminating thread damage and enabling simplified loosening and tightening of terminal  15  to terminal plate  14 . As a result, manufacturing costs and time are reduced and later operators of terminal connectors  100  work faster.  
         [0056]    Although only a single or few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiment(s) without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Thus although a nail and screw may not be structural equivalents in that a nail relies entirely on friction between a wooden part and a cylindrical surface whereas a screw&#39;s helical surface positively engages the wooden part, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures.  
         [0057]    Having described preferred embodiments of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.