Abstract:
A power plug structure is provided. The present invention includes a loop inductor, a top cover, a bottom cover, a terminal holder, a metal shell and a cable. The top cover and the bottom cover are vertically engaged with each other to form a space to accommodate the loop inductor. The terminal holder has a plate and a group of press-fit holes penetrating the plate. An upper press-fit hook of the top cover and a lower press-fit hook of the bottom cover are inserted into the press-fit holes from the rear side of the terminal holder to press-fit with the plate. The metal shell shelters the top cover and bottom cover. The cable has a plurality of wires respectively electrical connecting with wire grippers of the top cover. The abovementioned power plug structure is easy to assemble and has a wave-filtering function and a reliable structure.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a power plug structure, particularly to a power plug structure with high reliability. 
         [0003]    2. Description of the Related Art 
         [0004]    The daily-life, industrial electronic and electric devices are powered by alternating current, and the alternating current comes from a cable and a power plug connected with a power socket. Because of lacking a wave filter, many conventional power plugs lack an anti-noise function and an anti-electromagnetic interference function. In such a case, impulse current may cause early damage and a high failure rate. Although some conventional power plugs are equipped with a wave filter, the overall performance thereof is still inferior because of the following factors, including structural defects and insufficient protection of the rectifier unit. 
       SUMMARY OF THE INVENTION 
       [0005]    One objective of the present invention is to provide a power plug structure, wherein a top cover and a bottom cover are press-fitted to encase a loop inductor, and the integrated top cover and bottom cover are further press-fitted with a terminal holder, whereby the loop inductor is effectively protected, and the present invention is easy to assemble and has a reliable structure. 
         [0006]    To achieve the abovementioned objective, one embodiment of the present invention proposes a power plug structure, which comprises a loop inductor, a top cover, a bottom cover, a terminal holder, a metal shell and a cable. The loop inductor has a hollow portion. The top cover and the bottom cover are vertically engaged in a press-fit way to form a space to accommodate the loop inductor. At least one wire gripper and an upper press-fit hook respectively extend out from two laterals of the top cover. A lower press-fit hook extends out from a lateral of the bottom cover. The upper press-fit hook and the lower press-fit hook are arranged vertically. The openings of the upper and lower press-fit hooks are arranged in a face-to-face way or a back-to-back way. The terminal holder has a plate. A plurality of electric-conduction terminals protrudes from the front face of the plate. At least one positioning member is formed in the rear face of the plate and extends out with an angle existing between the plate and the positioning member. A group of press-fit holes penetrates the plate. The top cover and the bottom cover are pushed toward the plate from the rear face of the plate to insert the upper and lower press-fit hooks into the group of press-fit holes and secure the top and bottom covers to the plate. The metal shell wraps the top and bottom covers with the front face of the plate of the terminal holder being exposed. The cable has a plurality of wires, and each wire is electrically connected with an arbitrary one of the wire grippers. 
         [0007]    Below, the embodiments of the present invention are described in detail in cooperation with the attached drawings to make easily understood the objectives, technical contents, characteristics and accomplishments of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1 ,  FIG. 2A ,  FIG. 2B ,  FIG. 3  and  FIG. 4  are diagrams schematically showing the assemblage of a power plug structure according to one embodiment of the present invention; 
           [0009]      FIG. 5A  and  FIG. 5B  are diagrams schematically a power plug structure according to one embodiment of the present invention; 
           [0010]      FIG. 5C  is a sectional view along Line AA in  FIG. 5B ; 
           [0011]      FIG. 5D  is a partially enlarged view of  FIG. 5C ; and 
           [0012]      FIG. 6  is a diagram schematically showing a top cover and a bottom cover according to one embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]    The embodiments of the present invention are described in detail below. However, the embodiments are only to exemplify the present invention but not intended to limit the scope of the present invention. 
         [0014]    Refer to  FIG. 1 ,  FIG. 2A ,  FIG. 2B ,  FIG. 3 , and  FIG. 4  diagrams schematically showing the assemblage of a power plug structure according to one embodiment of the present invention. As shown in  FIG. 1 , the power plug structure comprises a loop inductor  110  having a hollow portion  112 . The loop inductor  110  may be formed via winding two independent coils on a magnetic ring, wherein the two independent coils have identical winding number but are respectively wound in opposite directions. A top cover  120  and a bottom cover  130  are vertically engaged in a press-fit way to form a space to accommodate the loop inductor  110 . An upper press-fit hook  122  and at least one wire gripper  124  respectively extend out from two laterals of the top cover  120 . In this embodiment, the upper press-fit hook  122  and the wire gripper  124  respectively extend out from a front side  121  and a rear side  123  of the top cover  120 . A lower press-fit hook  132  extends out from a lateral of the bottom cover  130 . In this embodiment, the lower press-fit hook  132  extends out from a front side  131  of the bottom cover  130 . The upper press-fit hook  122  and the lower press-fit hook  132  are corresponding to each other in the vertical direction. The opening  125  of the upper press-fit hook  122  and the opening  135  of the lower press-fit hook  132  are arranged in a face-to-face way or a back-to-back way. In this embodiment, the opening  125  of the upper press-fit hook  122  and the opening  135  of the lower press-fit hook  132  are arranged in a face-to-face way. 
         [0015]    Refer to  FIGS. 2A and 2B .  FIG. 2B  is a diagram schematically showing the assemblage of the power plug structure from another viewing angle. The power plug structure of the present invention further comprises a terminal holder  140  having a plate  142 . A plurality of electric-conduction terminals  144  protrudes from a front face  141  of the plate  142 . At least one positioning member  146  is formed on a rear face  143  of the plate  142  and extends out from the plate  142  with an angle existing between the positioning member  146  and the plate  142 . As shown in  FIG. 2B , a group of press-fit holes  148  penetrates the plate  142 . The upper press-fit hook  122  of the top cover  120  and the lower press-fit hook  132  of the bottom cover  130  are inserted into the press-fit holes  148  from the rear face  143  of the plate  140  to press-fit with the press-fit holes  148 . As long as the press-fit holes  148  can match the upper press-fit hook  122  of the top cover  120  and the lower press-fit hook  132  of the bottom cover  130 , the present invention does not limit the number of the press-fit holes  148 . 
         [0016]    Refer to  FIG. 2B  again. In one embodiment, the bottom cover  130  further comprises a press-fit slot  133 , and a rib  147  protrudes from the positioning member  146  of the terminal holder  140 , whereby the top cover  120  and the bottom cover  130  can be assembled to the terminal holder  140  via sliding the press-fit slot  133  of the bottom cover  130  along the rib  147 . Such a structure design makes the integrated top cover  120  and bottom cover  130  be firmly secured to the terminal holder  140 . 
         [0017]    As shown in  FIG. 3 , a metal shell  150  covers the assembled top cover  120 , bottom cover  130  and terminal holder  140  with a portion of the front face  141  of the plate  142  of the terminal holder  140  being exposed. In one embodiment, the metal shell  150  further comprises at least two side metal shells  152  and  154  covering the top cover  120  and the bottom cover  130  from two sides thereof The metal shell  150  may further comprise a rear metal plate  156 . In one embodiment, the rear metal plate  156  has an opening. However, the present invention does not demand that the rear metal plate  156  must have an opening. The rear metal plate  156  is assembled to the rear side of the top cover  120  and the bottom cover  130  to press-fit with the side metal shells  152  and  154  and cover a portion of the surfaces of the top cover  120  and bottom cover  130 . In one embodiment, the side metal shells  152  and  154  respectively have a plurality of protrusions  153  and a plurality of press-fit protrusions  153 ′, and the rear metal plate  156  has a plurality of press-fit holes  157 . The press-fit holes  157  of the rear metal plate  156  can press-fit with the protrusions  153  and  153 ′ of the side metal shells  152  and  154 . In one embodiment, the side metal shells  152  and  154  respectively have bent portions  155  and  155 ′. In assemblage, the side metal shells  152  and  154  are secured to the front face  141  of the terminal holder  140  via the bent portions  155  and  155 ′. 
         [0018]    Refer to  FIG. 4  a diagram schematically showing the semi-product of the power plug structure after the metal shell has been assembled. The metal shell  150  has an advantage of easy assemblage and has a function of shielding off electromagnetic interference. Next, a cable  160  having a plurality of wires  162  is assembled to the power plug structure after the metal shell  150  has been assembled. Each wire  162  is electrically connected with an arbitrary one of the wire grippers  124 . In one embodiment, the wire  162  is connected with the wire gripper  124  with a riveting method to effectively increase the efficiency of fabrication. 
         [0019]    Refer to  FIG. 5A  and  FIG. 5B . After the wires  162  have been assembled well, an insulating plastic shell  170  wraps the abovementioned components with the electric-conduction terminals  144  being exposed. Thus is formed the power plug structure shown in  FIG. 5A  and  FIG. 5B . The power plug structure shown in  FIG. 5A  is only one embodiment of the present invention. Any embodiments described in the specification are only to exemplify the present invention but not to limit the scope of the present invention. The technical characteristics of the present invention also apply to the power plug structures of the safety standards of other nations, such as China, USA, Canada, Swiss, Australia, Israel, etc. 
         [0020]      FIG. 5C  is a sectional view along Line AA in  FIG. 5B . The upper press-fit hook  121  of the top cover  120  and the lower press-fit hook  132  of the bottom cover  130  respectively pass the press-fit holes  148  of the terminal holder  140  to anchor on the terminal holder  140 . In one embodiment, there are two positioning members  146  and  146 ′ respectively vertically arranged on the rear face  143  of the plate  142 . After assemblage, the top cover  120  and the bottom cover  130  are interposed between the two positioning members  146  and  146 ′. As shown in the drawings, the two positioning members  146  and  146 ′ respectively press against the backsides of the top cover  120  and the bottom cover  130  lest the top cover  120  and the bottom cover  130  be separated by the pressure of plastic injection. Thereby, the loop inductor  110  is more effectively protected, and the reliability of the power plug structure is increased. 
         [0021]    In the abovementioned embodiments, it is described: the top cover  120  and the bottom cover  130  are press-fitted to encase the loop inductor  110 ; the press-fitted top cover  120  and bottom cover  130  is then press-fitted to the terminal holder  140 . However, how to press-fit the top cover  120  and the bottom cover  130  has not yet been described hereinbefore. Below will be described the press-fit mechanism of the top cover  120  and the bottom cover  130 . Refer to  FIG. 6 . A plurality of positioning protrusions  134  are formed along the rim  137  and/or in the accommodation space of the bottom cover  130 . The top cover  120  has a plurality of positioning recesses  126  corresponding to the positioning protrusions  134 . Thereby, the top cover  120  and the bottom cover  130  can be press-fitted to each other via the positioning protrusions  134  and the positioning recesses  126 . Refer to  FIG. 5D  a partially-enlarged view of  FIG. 5C . In one embodiment, the positioning protrusion  134  in the accommodation space of the bottom cover  130  is arranged on a first pillar  136 . The first pillar  136  protrudes from the interior of the bottom cover  130  and extends upward to pass through the hollow portion  112  of the loop inductor  110  to make the positioning protrusion  134  press-fit to the positioning recess  126  of the top cover  120 . In this embodiment, the positioning recess  126  is arranged on a second positioning pillar  128 . It should be understood that the positions of the positioning protrusions and the positioning recesses can be exchanged. In one embodiment, both the top cover  120  and the bottom cover  130  have positioning protrusions and positioning recesses at the same time. No matter how the positioning protrusions and positioning recesses are arranged in the abovementioned embodiments, the top cover and the bottom cover can always be press-fitted to each other. 
         [0022]    Refer to  FIG. 6  again. In one embodiment, the top cover  120  or the bottom cover  130  has a flange along the outer side of the rim. Herein, the flange  138  on the bottom cover  130  is used as an exemplification. When the top cover  120  is press-fitted to the bottom cover  130 , the rim  127  of the top cover  120  is also press-fitted to the inner face of the flange  138 . Such a design can assist in the positioning of the positioning protrusions. 
         [0023]    One characteristic of the present invention is that the electronic components of the loop inductor are integrated with the circuit inside the power plug structure. No matter whether the fluctuation of the power originates from the power supply network or is caused by the loads in the local network, the high impedances and magnetic fluxes induced by the common mode current of the AC circuit would be counterbalanced in the magnetic ring of the loop inductor. Therefore, the present invention can inhibit noise interference and electromagnetic interference and can prolong the service life of electronic devices and electric appliances. Another characteristic of the present invention is that a plurality of positioning protrusions and a plurality of positioning recesses corresponding to the positioning protrusions are formed on the top cover and the bottom cover to assist in the positioning of the top over and the bottom cover. Further, the backside of the bottom cover has press-fit slots matching the ribs of the terminal holder to guide the top cover and the bottom cover to be fast and precisely assembled to the terminal holder. Furthermore, the multiple side metal shells can be easily assembled to achieve a superior fixing effect without using any additional auxiliary. 
         [0024]    In conclusion, the present invention proposes a power plug structure, which can be easily assembled via integrating a top cover, a bottom cover and a terminal holder in an insertion way, and which has higher structural reliability and can effectively protect the loop inductor. 
         [0025]    The embodiments described above are to exemplify the present invention and demonstrate the technical thoughts and characteristics of the present invention to make the persons skilled in the art able to understand, make, and use the present invention. However, the embodiments are not intended to limit the scope of the present invention. Any equivalent modification or variation according to the spirit of the present invention is to be also included within the scope of the present invention.