Abstract:
A deflection yoke for preventing fluctuation of the deflection yoke by maintaining a firmly engaged state while preventing fracture and damage thereof caused by an assembling shock generated when assembling a printed circuit board and a rear cover. The printed circuit board has upper hook flaps protruded from a side surface of the rear cover including a plurality of slide grooves and lower hook flaps provided on the side of the upper hooks for penetrating holes is provided, the hook flaps are composed of supporting ribs and protrusions. Especially, the protrusions of the upper hook flap have an inclined angle to assemble the printed circuit board that is combined the rear cover stably.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a deflection yoke, and in particular, to a deflection yoke for preventing fluctuation of the deflection yoke by maintaining a firm engaged state while preventing fracture and damage thereof caused by an assembling shock generated when assembling the printed circuit board. 
     2. Description of the Prior Art 
     In general, a deflection yoke is employed for a TV set or a cathode ray tube (CRT) of a monitor to accurately deflect three-color beams scanned from an electron gun to a fluorescent screen coated on a screen of the CRT. The deflection yoke, which is the most significant factor of the magnetic devices of the CRT, plays a role of deflecting electron beams scanned from the electron gun so that the electric signals transmitted in time series can be reproduced as an image on the screen of the CRT. 
     To be specific, electron beams emitted from the electron gun travel straight forward the screen due to a high voltage, and illuminate a fluorescent body only at the center of the screen. Therefore, the deflection yoke plays a role of deflecting the electron beams so as to reach the screen in the order of being scanned from outside. This deflection yoke forms a magnetic field and uses a change of progressive direction by receiving power of the electron beams passing through the magnetic field so as to accurately deflect the electron beams to the coated fluorescent screen. 
     FIG. 1 is a side-elevational view of an ordinary CRT. As shown in FIG. 1, a deflection yoke  4  located at an RGB electron gun section  3  of a CRT  1  deflects electron beams scanned from an electron gun  3   a  to a fluorescent screen coated on a screen surface  2 . 
     This deflection yoke  4  comprises a pair of coil separators  10  symmetrically coupled in upper and lower directions. 
     The coil separator  10  provided for insulating a horizontal deflection coil  15  and a vertical deflection coil  16  as well as for assembling the same at proper positions comprises a screen section  11   a  engaged with a screen surface of the CRT  1 , a rear cover  11   b , and a neck section  12  integrally elongated from the central surface of the rear cover  11   b  to be engaged with the electron gun section  3 . 
     A horizontal deflection coil  15  and a vertical deflection coil  16  are provided on internal and outer peripheral surfaces of the coil separator  10  for forming a horizontal deflection magnetic field and a vertical deflection magnetic field with a power supply applied from outside. 
     A pair of ferrite cores  14  composed of a magnetic body are provided to surround the vertical deflection coil  16  for consolidating the vertical deflection magnetic field generated from the vertical deflection coil  16 . 
     When a sawtooth pulse is applied to the horizontal deflection coil  15  and the vertical deflection coil  16 , the deflection yoke  4  comprised as above determines a scanning position on the screen by deflecting the electron beams of red (R), green (G) and blue (B) emitted from the electron gun  3   a  of the CRT due to a magnetic field generated according to the Fleming&#39;s left-hand rule. 
     Meanwhile, the deflection yoke as shown in FIG. 1 is roughly classified into a saddle-saddle type deflection yoke as shown in FIGS. 2 and 3, and a saddle-toroidal type deflection yoke as shown in FIGS. 4 and 5 in accordance with a winding structure of the coil. 
     In the saddle-saddle type deflection yoke shown in FIGS. 2 and 3, the horizontal deflection coil  15  of a saddle shape is installed on upper and lower sides of the internal periphery of the screen section of the coil separator  10  of a cone shape. 
     To reinforce the magnetic field of the vertical deflection coil  16 , the ferrite cores  14  of a cylindrical shape are provided on an external surface of the screen section  11   a  of the coil separator  10 . 
     A coma-free coil (not shown in the drawings) is installed around an external periphery of the neck section  12  of the coil separator  10  for correcting coma generated by the vertical deflection coil  16 . 
     FIGS. 4 and 5 are views showing an ordinary deflection yoke of a saddle-toroidal type. A horizontal deflection coil is installed on upper and lower sides of the internal peripheral surface of the screen section  11   a  of the coil separator  10  of a cone shape, and the ferrite cores  14  of a cylindrical shape are provided on an outer peripheral surface of the screen section  11   a . A vertical deflection coil  16  of a toroidal type is wound along the upper and lower sides of the ferrite cores  14 . 
     A coma-free coil (not shown in the drawings) is additionally installed around the periphery of the neck section  12  of the coil separator  10  for correcting coma generated by the vertical deflection coil  16 . 
     In the saddle-saddle type deflection yoke and the saddle-toroidal type deflection yoke, a printed circuit board is additionally installed on one side surface of the coil separator  10  for supplying power to the aforementioned horizontal deflection coil  15  and the vertical deflection coil  16 . 
     FIGS. 6 and 7 are views illustrating assembled states of the printed circuit board in the conventional deflection yoke. As shown in FIGS. 6 and 7, a printed circuit board  100  is engaged with a side surface of the rear cover  11   b  of the coil separator  10  for electrically connect the deflection coils and diverse electric automotive equipments. 
     A plurality of penetrating holes  110  are formed at predetermined positions of the printed circuit board  100  with regular intervals. A pair of hook flaps  200  are protruded from the rear cover lib corresponding to the penetrating holes  110  for fixing the printed circuit board  100  without fluctuation. 
     Here, in the pair of hook flaps  200 , protrusions  210  having a triangular flap shape, i.e., slopes extended from a front end to a rear end thereof, are formed at end portions thereof so as to be suspended on one side surface of the printed circuit board  100  upon penetration of the penetrating holes  110 . 
     The pair of hook flaps  200  are distanced to be slightly farther than the distance between the pair of penetrating holes  110  so that one surface perpendicular to the protrusions  210 , i.e., the suspending threshold can support one side surface of the printed circuit board  100  after being elastically inserted to the penetrating holes  110 . 
     Supporting ribs  220  are elongated to the hook flaps  200  so that the protrusions  210  penetrating the penetrating holes  110  press one side surface of the printed circuit board  100  when in contact with the other side surface of the printed circuit board  100 . 
     The supporting ribs  220  having a predetermined area in a board plank shape is provided to extensively support one side surface of the printed circuit board. 
     In other words, the protrusions  210  integrally formed with the hook flaps  200  and the supporting ribs  220  fix the printed circuit board  100  by being in contact with the respective sides of the printed circuit board  100 . 
     In the conventional deflection yoke having the above construction, the printed circuit board  100  is fixed onto the coil separator  100 , i.e., on the rear cover  11   b , by being suspended by the hook flaps  200  integrally protruded from the rear cover  11   b  and by being supported by the supporting ribs  220  elongated to the hook flaps  200 . 
     However, such a conventional deflection yoke poses the following problems as the assembling structure between the printed circuit board  100  and the rear cover  11   b  is made by the pair of hook flaps  200  and the penetrating holes  110 . 
     To be specific, as shown in FIG. 7, a worker needs to forcibly insert the printed circuit board  100  to the hook flaps  200  in order to fix the printed circuit board  100  onto the rear cover  11   b . In this process, the assembling force laid on the printed circuit board  100  by the worker causes a fracture of the printed circuit board  100  or a deformation of the hook flaps  200 . 
     Moreover, the printed circuit board  100  and the rear cover  11   b  have a structure of being engaged by the pair of penetrating holes  110  and the hook flaps  200 . Therefore, if a forming dispersion or an assembling dispersion is generated in the penetrating holes  110  and the hook flaps  200 , the printed circuit board  100  is not stably fixed on the rear cover  11   b  but is fluctuated. 
     The above problems not only increase defective proportion of the products but also notably deteriorate the quality of products due to failure of firmly fixing the printed circuit board  100  onto the rear cover  11   b.    
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide a deflection yoke which can maintain a firm engaged state while reducing fracture and damage of the parts caused by an assembling force laid by a worker when fixing a printed circuit board onto a rear cover. 
     To achieve the above object, there is provided a deflection yoke, comprising: a coil separator including a screen section engaged with a screen surface of a CRT, a rear cover, and a neck section elongated from a central surface of the rear cover to be engaged with an electron gun section of the CRT; horizontal and vertical deflection coils provided on internal and outer peripheral surfaces of the coil separator for forming horizontal and vertical deflection magnetic fields; a printed circuit board engaged with the rear cover of the coil separator and having a plurality of slide grooves connected to a frame on an upper portion thereof and a plurality of penetrating holes formed beneath the slide grooves at regular intervals for electrically connecting each of electronic parts; upper hook flaps protruded from a side surface of the rear cover to have supporting ribs contacted with one surface of the printed circuit board at one end thereof and protrusions contacted with the other surface of the printed circuit board upon penetration of the slide grooves at the other end thereof; a lower hook flap provided on one side of the upper hook flap to have supporting ribs and protrusions for supporting both side surfaces of the printed circuit board by penetrating the same; and a guiding slope surface formed on the sides of the supporting ribs or protrusions to have a predetermined angle so that the printed circuit board can enter the space between the supporting ribs and the protrusions of the upper hook flaps with a predetermined angle. 
     The guiding slope surface according to the present invention is characterized by being formed on a side of the protrusions facing the supporting ribs of the upper hook flaps. 
     The guiding slope surface according to the present invention is further characterized by being formed on a side of the supporting ribs facing the protrusions of the upper hook flaps. 
     The guiding slope surface according to the present invention is also characterized by being formed within an angle range of 5-60°. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a side-elevational view of a CRT in general; 
     FIG. 2 is a front view of a deflection yoke of a saddle-saddle type in general; 
     FIG. 3 is a top-plan view of a deflection yoke of a saddle-saddle type in general; 
     FIG. 4 is a front view of an ordinary saddle-toroidal type deflection yoke; 
     FIG. 5 is a top-plan view of an ordinary saddle-toroidal type deflection yoke; 
     FIGS. 6 and 7 are views illustrating assembled states of a printed circuit board in a conventional deflection yoke; 
     FIG. 8 is a view illustrating an assembled state of a printed circuit board in a deflection yoke according to an embodiment of the present invention; 
     FIG. 9 is a side-elevational view of a rear cover in FIG. 8; 
     FIG. 10 is a side-elevational view of a printed circuit board as being assembled in FIG. 8; 
     FIG. 11 is a side-elevational view of an assembled printed circuit board in FIG. 10; and 
     FIG. 12 is a side-elevational view of a rear cover according to another embodiment of the present invention in FIG.  9 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. In the following description, same drawing reference numerals are used for the same elements even in different drawings. The matters defined in the description such as a detailed construction and elements of a circuit are nothing but the ones provided to assist in a comprehensive understanding of the invention. Thus, it is apparent that the present invention can be carried out without those defined matters. Also, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. 
     Referring to FIGS. 1 to  5 , the ordinary deflection yoke  4  shown in FIG. 1 is located at the RGB electron gun section  3  of the CRT  1  for deflecting electron beams scanned from the electron gun  3   a  to a fluorescent screen coated on the screen surface  2 . In accordance with the winding structure of a coil, deflection yokes are roughly classified into a saddle-saddle type deflection yoke as shown in FIGS. 2 and 3, and a saddle-toroidal type deflection yoke as shown in FIGS. 4 and 5. 
     The deflection yoke  4  plays a role of deflecting electron beams emitted from the electron gun  3   a  of R, G, B installed inside of the neck section  12  of the CRT  1  toward left, right, upper and lower directions so as to be collided with an accurate position on the fluorescent surface of the CRT. 
     FIGS. 2 and 3 are views of a saddle-saddle type deflection yoke. As shown in FIGS. 2 and 3, the horizontal deflection coil  15  of a saddle-saddle type is installed on upper/lower sides of inner peripheral surface of the screen section  11   a  of the coil separator  10  of a cone shape, while the vertical deflection coil  16  of a saddle-saddle type is installed on left/right sides of the outer peripheral surface. 
     To reinforce magnetic field of the vertical deflection coil  16 , the ferrite cores  14  of a cylindrical shape are provided on an outer peripheral surface of the screen section  11   a  of the coil separator  10 . 
     A coma-free coil (not shown in the drawings) is installed around an external periphery of the neck section  12  of the coil separator  10  to correct coma generated by the vertical deflection coil  16 . 
     FIGS. 4 and 5 are views of an ordinary saddle-toroidal type deflection yoke. The horizontal deflection coil  15  is installed on upper and lower sides of the inner peripheral surface of the screen section  11   a  of the coil separator  10  of a cone shape. The ferrite cores  14  of a cylindrical shape are provided on an outer peripheral surface of the screen section  11   a . The vertical deflection coil  16  of a toroidal type is wound along the upper and lower sides of the ferrite cores  14 . 
     A coma-free coil (not shown in the drawings) is additionally installed around the external periphery of the neck section  12  of the coil separator  10  to correct coma generated by the vertical deflection coil  16 . 
     In the deflection yokes of a saddle-saddle type and a saddle-toroidal type, a printed circuit board is installed on one side surface of the coil separator  10  for supplying power to the aforementioned horizontal deflection coil  15  and the vertical deflection coil  16 . 
     Meanwhile, as shown in FIGS. 8 to  12 , the horizontal deflection coil  15 , the vertical deflection coil  16 , and the printed circuit board  30  for electrically connecting diverse electric automotive products are engaged with a side surface of the rear cover  11   b  of the coil separator  10 . The printed circuit board  30  is constructed so as to receive a power supply from outside. 
     The printed circuit board  30  engaged with the rear cover  11   b  of the coil separator  10  has a plurality of slide grooves  31  at regular intervals on both side surfaces of an upper portion thereof as shown in FIG.  8 . 
     The slide grooves  31  are a kind of slits elongated from an upper frame toward a lower side of the printed circuit board  30  as shown in FIG.  8 . According to the present invention, a pair of slide grooves are provided on an upper side of the printed circuit board  30  at regular intervals. 
     In the printed circuit board  30 , a pair of penetrating holes  32  are formed on a lower side of the slide grooves  31 . 
     The upper hook flaps  40  and the lower hook flap  45  are provided on the rear cover  11   b  corresponding to the slide grooves  31  and the penetrating holes  32  formed on the printed circuit board  30  to firmly fix the printed circuit board  30 . 
     Here, the upper hook flaps  40  are formed in a pair on a side surface of the rear cover  11   b  corresponding to the slide grooves  31  of the printed circuit board  30  so as to be inserted to the pair of slide grooves  31 . 
     In the upper hook flaps  200 , protrusions having a triangular flap shape are formed at end portions thereof so as to be suspended upon penetration of the sliding grooves  31 . Supporting ribs  41  are formed to be vertically elongated from the protrusions at predetermined positions with regular intervals. 
     The pair of hook flaps  40  are distanced to be slightly wider than the distance between the pair of slide grooves  31  so as to be elastically inserted to the slide grooves  31 . 
     The supporting ribs  41  formed on the upper hook flaps  40  are extensively in contact with an area adjacent to the inner side of the printed circuit board  30  to prevent fluctuation of the printed circuit board  30  together with the protrusions, and have a board plank shape of being parallel with the ordinary printed circuit board  30 . 
     The supporting ribs  41  are formed to have a board plank shape in a horizontal direction opposed to one end of the upper hook flaps  40  as shown in FIG.  8 . However, the shape of the supporting ribs  41  is not limited to the board plank shape but may be variable provided that the structure of the shape can firmly support the other surface of the printed circuit board  30 . 
     If the protrusions formed at the end portion of the upper hook flaps  40  penetrate the slide grooves  31 , one side surface of the protrusions is in contact with one surface of the printed circuit board  30 . At this stage, the supporting ribs  41  formed at regular intervals with the protrusions are in contact with the other surface of the printed circuit board  30 . 
     The printed circuit board  30  is thus fixed onto the upper hook flaps  40  by a contact of the both side surfaces thereof centering around the slide grooves  31  with the supporting ribs  41  and the protrusions of the upper hook flaps  40 . 
     Meanwhile, protrusions of a triangular flap shape are formed at an end portion of the lower hook flaps  45  formed on a lower side of the upper hook flaps  40 , as in case of the upper hook flaps  40 , and supporting ribs  46  are formed at regular intervals with the protrusions. 
     The lower hook flaps  45  are distanced slightly farther than the distance between the pair of penetrating holes  32  formed on a printed circuit board  30  so as to be elastically inserted to the penetrating holes  32 . 
     The supporting ribs  46  formed on the lower hook flaps  45  are extensively in contact with an area adjacent to the inner side of the printed circuit board  30  to prevent fluctuation of the printed circuit board  30  together with the protrusions, and have a board plank shape of being parallel with the ordinary printed circuit board  30 . 
     The supporting ribs  46  are formed to have a board plank shape in a horizontal direction opposed to one end of the pair of lower hook flaps  45  as shown in FIG.  8 . However, the shape of the supporting ribs  46  is not limited to the board plank shape but may be variable provided that the structure of the shape can firmly support the other surface of the printed circuit board  30 . 
     If the lower hook flaps  45  constructed as above penetrate the penetrating holes  32  of the printed circuit board  30 , one surface of the protrusions is in contact with one surface of the printed circuit board  30 , while the supporting ribs  46  are in contact with the other surface the printed circuit board  30 . 
     Thus, the printed circuit board  30  is fixed onto the lower hook flaps  45  by a contact of both side surfaces thereof centering around the penetrating holes  32  with the supporting ribs  46  and the protrusions of the lower hook flaps  45 . 
     The upper hook flaps  40  and the lower hook flaps  45  are respectively inserted to the slide grooves  31  and the penetrating holes  32  formed on the printed circuit board  30  so as to firmly fix the printed circuit board  30 . 
     Meanwhile, to facilitate assembly of the printed circuit board  30 , a guiding slope surface  50  having a slope angle ranged about 5-60° is formed on one side of the protrusions as shown in FIG.  9 . 
     This means that the guiding slope surface  50  formed on one side of the protrusions of the upper hook flaps  40  allows the printed circuit board  30  to enter the cleavage between the protrusions and the supporting ribs  41  of the upper hook flaps  40  with a predetermined angle as shown in FIG.  10 . 
     The guiding slope surface  50  can not only be formed on the protrusions of the upper hook flaps  40  but also may be formed on a side surface of the supporting ribs  41  facing the protrusions of the upper hook flaps  40  as shown in FIG.  12 . 
     An assembling process of the printed circuit board in a deflection yoke according to the present invention will now be described. 
     In order to fix the printed circuit board  30  onto the rear cover  11   b , an upper portion of the printed circuit board  30  shown in FIG. 10, i.e., the pair of slide grooves  31 , are inserted to the pair of upper hook flaps  40  formed on a side surface of the rear cover  11   b.    
     Since the guiding slope surface  50  having a slope surface of a predetermined angle is formed on the protrusions of the pair of upper hook flaps  40 , the slide grooves  31  can be easily inserted along one end of the upper hook flaps  40  with no difficulty if the printed circuit board  30  inserted between the protrusions and the supporting ribs  41  of the upper hook flaps  40  is inclined with an entry angle, i.e., with an angle inclined for assembly. 
     Subsequently, if the slide grooves  31  of the printed circuit board  30  are suspended between the protrusions and the supporting ribs  41  of the upper hook flaps  40 , the lower side of the printed circuit board  30  is moved toward the lower hook flaps  45  centering around the suspended part, i.e., centering around the upper hook flaps  40  and the slide grooves  31 . 
     Then, the penetrating holes  32  of the printed circuit board  30  approach the lower hook flaps  45 , and the lower hook flaps  45  cause a slightly elastic displacement along the slope surface of the printed circuit board  30  so that the lower hook flaps  45  can be inserted to the penetrating holes  32  as shown in FIG.  11 . At the same time, the slide grooves  31  are completely inserted and fixed onto the upper hook flaps  40 . 
     Accordingly, fracture of the printed circuit board  30  can be prevented in advance as the shocking force and external force generated during an assembly are reduced because the penetrating holes  32  are fixed onto the lower hook flaps  45  under the state that the printed circuit board  30  is inclined and the upper hook flaps  40  having the guiding slope surface  50  have entered the slide grooves  31 . 
     The assembling efficiency of the printed circuit board  30  thus being drastically improved, productivity of the printed circuit board  30  can also be enhanced, and a low quality of the product caused by fracture of the printed circuit board and the hook flaps in the assembling process can be prevented in advance. 
     While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.