Abstract:
An electric plug is constructed to include a front housing having a plurality of notches formed in aligned manner along a rear side thereof. A set of conducting blades are mounted in the front housing such that they extend outward in a direction perpendicular to a front side of the front housing for insert into an electric outlet. The conducting blades are formed with rear ends which respectively extend into the notches of the front housing. A rear housing is pivotally coupled to the front housing, and a set of metal terminals are mounted in the rear housing and respectively pivoted to the rear ends of the conducting blades for enabling the rear housing to be turned relative to the front housing between two positions within 90 degrees.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electric plug and, more particularly, to such an electric plug, which is comprised of a front housing holding a set of conducting blades, and a rear housing hinged to the front housing and holding a set of metal terminals, which are respectively pivoted to the conducting blades for enabling the rear housing to be turned relative to the front housing between two positions within 90°. 
     2. Description of the Related Art 
     FIG. 1 illustrates an electric plug  1  according to the prior art. This structure of electric plug  1  comprises an electrically insulative housing  12 , and two conducting blades  1  axially forwardly extended out of the front side of the housing  12 . According to this design, the housing  12  is perpendicularly protruded from the front side of the electric outlet after installation of the electric plug. FIG. 2 illustrates another structure of electric plug according to the prior art. According to this design, the electric plug  2  comprises an electrically insulative housing  22 , two conducting blades  21  perpendicularly extended out of the housing  22 , and a pull ring  24  pivoted to the housing  22 . This design occupies less installation space. Through the pull ring  24 , the user can pull the electric plug  2  away from the electric outlet with less effort. However, when pulling the pull ring  24 , a concentration of stress is produced, and the housing  22  tends to be damaged, causing the pull ring  24  to disconnect from the housing  22 . This design of electric plug occupies less vertical installation space, however it occupies much horizontal installation space. When the electric plug  2  installed in an electric outlet in the wall near the floor, the power cord  23  of the electric plug  2  may have to be bent to a particular direction. In this case, the inside conductors of the power cord  23  tend to be broken. FIG. 3 shows still another structure of electric plug according to the prior art (Taiwan Patent Publication No. 431695). According to this design, the electric plug  3  comprises a bottom cover shell  31 , a wheel  32 , two conducting blades  33 , two metal terminals  34 , a power cord  35 , and a top cover shell  36 . The conducting blades  33  are coupled to the wheel  32  and respectively pivoted to the metal terminals  34 . The wheel  32  can be rotated in front openings  311 ; 361  of the cover shells  31 ; 36 . When in use, as shown in FIG. 4, the cover shells  31 ; 36  can be turned with the metal terminals  34  relative to the conducting blades  33  and the wheel  32  within 180° (90° leftwards and 90° rightwards). However, when the electric plug  3  installed in the left socket unit  371  of a multi-socket electric outlet  37 , the electric plug  3  will block the adjacent socket unit  372  of the electric outlet  37  if the user turn the cover shells  31 ; 36  to the right side relative to the conducting blades  33 . Further, this design is not suitable for a three-pole electric plug fitting a three-pole electric socket. 
     Therefore, it is desirable to provide an electric plug that eliminates the aforesaid drawbacks. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished to provide an electric plug, which eliminates the aforesaid drawbacks. It is one object of the present invention to provide an electric plug, which can be alternatively set between two positions to minimize the occupation of installation space. It is another object of the present invention to provide an electric plug, which is suitable for a two-pole design as well as a three-pole design. To achieve these and other objects of the present invention, the electric plug comprises a front housing formed of a bottom cover shell and a top cover shell, the front housing comprising a plurality of insertion slots in the bottom cover shell thereof, and a plurality of notches in a rear side thereof; a rear housing formed of a bottom cover shell and a top cover shell and pivoted to the front housing, the rear housing comprising a plurality of knuckles protruded from a front side thereof and respectively pivoted to the notches of the front housing; a plurality of conducting blades mounted in the housing and respectively extended out of the insertion slots of the front housing in direction perpendicular to a front side of the front housing, the conducting blades each having a rear end respectively suspended in the notches of the front housing; and a plurality of metal terminals mounted in the rear housing and connected to a power cord, the metal terminals each having a front end respectively pivoted to the rear ends of the conducting blades in the notches of the front housing for enabling the rear housing to be turned relative to the front housing between a first position where the front housing and the rear housing are maintained horizontally aligned, and a second position where the front housing and the rear housing are maintained at right angles. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational view of an electric plug according to the prior art. 
     FIG. 2 is an elevational view of another structure of electric plug according to the prior art. 
     FIG. 3 is an exploded view of still another structure of electric plug according to the prior art. 
     FIG. 4 is a schematic drawing showing the application of the electric plug of FIG.  3 . 
     FIG. 5 is a schematic drawing showing one application example of an electric plug constructed according to the present invention. 
     FIG. 6 is an exploded view of an electric plug according to one embodiment of the present invention. 
     FIG. 7 is an elevational view, in a part, of the electric plug according to the present invention, showing the conducting blades respectively pivoted to the metal terminals. 
     FIG. 7A is a top view of FIG.  7 . 
     FIG. 7B is similar to FIG. 7 but showing a ground conducting blade provided and pivoted to a grounding metal terminal. 
     FIG. 8 is a schematic drawing of the present invention showing the rear housing turned relative to the front housing between the first position and the second position within 90°. 
     FIG. 9 is a sectional view taken along line  9 — 9  of FIG.  8 . 
     FIG. 10 is a sectional view taken along line  10 — 10  of FIG.  9 . 
     FIG. 11 is corresponding to FIG. 10, showing the rear housing turned between the first position and the second position. 
     FIG. 12 is corresponding to FIG. 8 but showing the electric plug provided with a grounding conducting blade. 
     FIG. 13 is a sectional view taken along line  13 — 13  of FIG.  12 . 
     FIG. 14 is a schematic drawing showing the rear housing turned to the second position, the user&#39;s fingers pressed on the recessed portions of the rear housing and hooked on the front protruded portion of the front housing. 
     FIG. 15 illustrates another alternate form of the electric plug. 
     FIG. 16 is an exploded view of still another alternate form of the electric plug according to the present invention. 
     FIG. 17 is a side view of the electric plug of FIG. 16, showing the hanger hooked on the transverse locating groove of the front housing. 
     FIG. 18 is another side view of the electric plug of FIG. 16, showing the hanger hooked on the front protruded portion of the front housing. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 5-9, an electric plug in accordance with the present invention is shown comprising two conducting blades  41 ;  42 , two metal terminals  51 ;  52 , a front housing  6 , and a rear housing  7 . 
     The conducting blades  41 ; 42  are adapted for connecting to the positive and negative poles of power source, each having an extension mounting portion  411  or  421  extended from one end, namely, the rear end thereof at right angles and a pivot hole  412  or  422  in the extension mounting portion  411  or  421 . The extension mounting portions  411 ; 421  of the conducting blades  41 ; 42  have different lengths such that the pivot holes  412 ; 422  are aligned in axis X-X when the conducting blades  41 ; 42  installed in the front housing  6 . 
     The metal terminals  51 ; 52  are respectively connected to the positive pole conductor and negative pole conductor of a power cord  54 , each having a front end respectively pivotally riveted to the pivot holes  412 ; 422  of the conducting blades  41 ; 42  by rivets  511 ; 521 . 
     The front housing  6  is comprised of a top cover shell  6   a  and a bottom cover shell  6   b . The bottom cover shell  6   b  comprises two insertion slots  61 ; 62  through which the conducting blades  41 ; 42  extend to the outside of the front housing  6  for inserting into the one of the socket units  371 ; 372  of an electric outlet  37 . The top cover shell  6   a  and the bottom cover shell  6   b  each have two notches  63  disposed at a rear side corresponding to the rivet position (axis X-X) between the conducting blades  41 ; 42  and the metal terminals  51 ; 52 . After installation of the conducting blades  41 ; 42  in the front housing  6 , the conducting blades  41 ; 42  extend perpendicularly out of the front side of the bottom cover shell  6   b  of the front housing  6  through the insertion slots  61 ; 62  (see FIG.  8 ). 
     The rear housing  7  is comprised of a top cover shell  7   a  and a bottom cover shell  7   b . The top cover shell  7   a  and the bottom cover shell  7   b  are fastened together to hold the metal terminals  51 ; 52  on the inside. The rear housing  7  has front knuckles  71  pivoted to the notches  63  of the front housing  6 . When assembled, the rear housing  7  can be turned with the metal terminals  51 ; 52  relative to the front housing  6  and the conducting blades  41 ; 42  between a first position where the front housing  6  and the rear housing  7  are aligned on a plane (see FIG.  10 ), and a second position where the front housing  6  and the rear housing  7  are maintained at right angles (see FIG.  11 ). 
     Referring to FIG.  7  and FIG. 7A, the extension mounting portions  411  or  421  are respectively extended from the conducting blades  41 ; 42  at right angles and positioned in area I (inside the front housing  6 ), keeping the pivot holes  412 ; 422  aligned on axis X-X and respectively pivoted to the metal terminals  51 ; 52  by rivets  511 ; 521 . Further, the rear ends  513 ; 523  of the metal terminals  51 ; 52  can be riveted or soldered to the positive pole conductor and negative pole conductor of a power cord  54  (see FIG.  7 ). 
     Alternatively, the electric plug can be made having three blades. As shown in FIG. 7B, a grounding conducting blade  43  is provided having rear extension mounting portion  431  spaced between the extension mounting portions  411 ; 421  of the conducting blades  41 ; 42  and pivoted to a grounding metal terminal  53 . 
     The top cover shell  6   a  and bottom cover shell  6   b  of the front housing  6  are respectively molded from plastics, and sealed together by a high-frequency heat sealing apparatus after installation of the conducting blades  41 ; 42  in the bottom cover shell  6   b . The thickness of the front housing  6  is simply slightly thicker than the heights  413 ; 423  of the extension mounting portions  411 ; 421  of the conducting blades  41 ; 42 . Therefore, the front housing  6  is shaped like a flat case. Because the front knuckles  71  of the rear housing  7  are pivoted to the notches  63  of the front housing  6  and the conducting blades  41 ; 42  are respectively pivoted to the metal terminals  51 ; 52 , the rear housing  7  and the front housing  6  can be aligned on a plane without occupying much space (see FIGS.  5 ˜ 8 ). When installed in one socket unit  371  of a multi-socket electric outlet  37 , the rear housing  7  can be turned to the second position perpendicular to the front housing  6  (see FIG. 11) so as not to block the adjacent socket unit  372  of the multi-socket electric outlet  37  (see also FIG. 5) 
     Further, the conducting blades  41 ; 42  and the metal terminals  51 ; 52  have a respective locating notch  414 ,  424 ,  512 , or  522  respectively engaged with a respective rib  66  or  72  in the front housing  6  or rear housing  7 . The front housing  6  has a front protruded portion  64 . The rear housing  7  has two recessed portions  74  at two opposite lateral sides. When the rear housing  7  turned to the second position perpendicular to the front housing  6 , the user can easily pull the electric plug away from the electric outlet  37  with the fingers pressed on the recessed portions  74  and hooked on the front protruded portion  64  (see FIG.  14 ). 
     Because the conducting blades  41 ; 42  extend perpendicularly out of the front side of the bottom cover shell  6   b  of the front housing  6 , the front housing  6  is maintained closely attached to the electric outlet when the conducting blades  41 ; 42  inserted into the insertion slots of the electric outlet  37  (see FIG.  14 ). 
     Referring to FIGS. 12 and 13, the rear extension mounting portion  431  of the grounding conducting blade  43  is pivoted to the grounding metal terminal  53  in the rear housing  7  at a location in axis X-X, i.e., in line with the pivoted points between the conducting blades  41 ; 42  and the metal terminals  51 ; 52 . Therefore, the metal terminals  51 ; 52 ; 53  can be turned with the rear housing  7  relative to the conducting blades  41 ; 42 ; 43  and the front housing  6  between the first position and the second position within 90°. 
     Referring to FIG. 14 again, when pulling the electric outlet outwards from the electric outlet  37  after the rear housing  7  set in the second position, the pulling force can be concentrated to the direction in axial alignment to the conducting blades  41 ; 42 ; 43  (the insertion slots of the electric outlet  37 ), therefore the user can pull the electric plug out of the electric outlet with less effort. 
     Referring to FIG. 15, the conducting blades  41 ; 42 ; 43  can be so positioned in the front housing  6  that the front housing  6  and rear housing  7  of the electric plug are disposed outside the electric outlet  37  in an oblique position without blocking the adjacent second socket unit  373  after insertion of the conducting blades  41 ; 42 ; 43  into the insertion slots of one socket unit of the electric outlet  37 . 
     Referring to FIGS.  16 ˜ 18 , a retaining member, for example, a hanger  8  is pivoted to the rear housing  7  and adapted for holding the rear housing  7  in the first position or the second position alternatively. The rear housing  7  comprises two pivot holes  75  respectively disposed at two sides. The front housing  6  comprises a transverse locating groove  65 . The hanger  8  comprises a front hanger rod  82 , and two endpieces  81  respectively extended from two distal ends of the front hanger rod  82  and respectively pivoted to the pivot holes  75  of the rear housing  7 . When the rear housing  7  turned to the first position, the hanger rod  82  is forced into engagement with the transverse locating groove  65  of the front housing  6  to hold the rear housing  7  positively in the first position (see FIG.  17 ). When locking the rear housing  7  in the second position, turn the rear housing  7  to the second position and then keep forcing the rear housing  7  forwards over the vertical axis Y-Y to axis Y′-Y′ (see FIG. 18) for enabling the hanger rod  82  to be moved over the front protruded portion  64  of the front housing  6  and then hooked up with the front protruded portion  64 . When the hand released from the rear housing  7  after the hanger rod  82  hooked up with the front protruded portion  64  of the front housing  6 , the rear housing  7  is returned to the second position in coincidence with the vertical axis Y—Y by the springy material property of the housings  6 ; 7 . 
     A prototype of electric plug has been constructed with the features of FIGS.  5 ˜ 18 . The electric plug functions smoothly to provide all of the features discussed earlier. 
     Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.