Patent Publication Number: US-2005134998-A1

Title: Pole base assembly for magnetic recording and reproducing apparatus and the magnetic recording and reproducing apparatus employing the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application claims the benefit under 35 U.S.C. § 119(a) of Korean Patent Application No. 2003-95752 filed on Dec. 23, 2003 in the Korean Intellectual Property Office, the entire disclosure of which is hereby incorporated by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a magnetic recording and reproducing apparatus. More particularly, the present invention relates to a pole base assembly for a magnetic recordingand reproducing apparatus that is adapted to move a magnetic tape into close contact with a head drum at the time of loading of the magnetic tape and to run in close contact with the head drun during running of the magnetic tape. The present invention also relates to a magnetic recording and reproducing apparatus employing such a pole base assembly.  
      2. Description of the Related Art  
      Typically, a magnetic recording and reproducing apparatus having a deck mechanism, such as a video tape recorder (VTR) or a camcorder, is an apparatus for recording data into and reproducing data from a magnetic tape while the magnetic tape is running along a predetermined route formed within the deck.  
       FIG. 1  shows a deck typically employed in a camcorder among magnetic recording and reproducing apparatuses as described above. A conventional deck  100  includes a deck chassis  10 , a head drum  30 , and a pair of pole base assemblies  50 . In the drawing, reference numerals  40 ,  60  and  70  respectively indicate a tension pole assembly, a pinch roller, and a review pole assembly, which form a running route of a magnetic tape, and reference numeral  80  indicates a capstan drive unit for providing power required for the running of the magnetic tape.  
      The deck chassis  10  forms the outer wall of the deck  100  and various driving components for recording and reproducing of data, such as the head drum  30 , the pole base assemblies  50 , etc., are disposed in the deck chassis  10 .  
      The head drum  30  records data onto a magnetic tape  1  running within the deck  10  or reproduces the data recorded in the magnetic tape  1 . As is well-known in the art, such a head drum  30  is installed to be slanted by a predetermined angle θ (see  FIG. 6 ) in relation to a reference surface H (see  FIG. 6 ), which is parallel to the bottom surface of the deck chassis  10 , so that recording/reproducing of data may be efficiently implemented.  
      Each pole base assembly  50  draws the magnetic tape  1  out of a tape cassette  90  at the time of loading the magnetic tape  1  to bring the magnetic tape  1  into close contact with the head drum  230  and to guide the magnetic tape  1  to run while being in contact with the head drum  30 .  
      The conventional pole base assembly  50  includes a base member  51 , a pole member  53 , and a guide roller  55  as shown in  FIG. 2 . The base member  51  is slidably installed on a guide rail  11  provided on the deck chassis  10 . With this arrangement, the base member  51  is moved along the direction indicated by arrow A to a loading position PI (see  FIG. 1 ) adjacent to the head drum  30 . The pole member  53  and the guide roller  55  extend from the top surface of the base member  51  and are moved into contact with the magnetic tape  1  at the time of loading the magnetic tape  1 , thereby bringing the magnetic tape  1  into close contact with the head drum  30 . In addition, when the magnetic tape runs after the completion of the loading of the magnetic tape  1 , the pole member  53  and the guide roller  55  guide the running of the magnetic tape  1  so that the magnetic tape  1  runs in close contact with the head drum  30 . Here, the pole member  53  is installed to be positioned parallel to the circumferential surface of the head drum  30 , which is installed to be slanted in relation to the bottom surface of the deck chassis  10  in the state in which the loading of the magnetic tape  1  has been completed. By the pole member  53 , the running direction of the magnetic tape  1  is diverted to the head drum  30  side. The guide roller  55  serves to align the top and bottom positions of the magnetic tape  1  prior to contacting the pole member  53  and includes upper and lower flanges  57  and  56  to contact the top and bottom edges of the magnetic tape  1 , respectively.  
      With the conventional deck  100  configured as described above, each of the pole base assemblies  50  are provided with both the pole member  53  and the guide roller  55 , as shown in  FIG. 2 . Therefore, there is a problem in that it is not easy to reduce the manufacturing costs and steps for such a magnetic recording and reproducing apparatus. In addition, there is also a problem in that it is difficult to miniaturize such a magnetic recording and reproducing apparatus.  
     SUMMARY OF THE INVENTION  
      Accordingly, an object of the present invention is to provide a pole base assembly for a magnetic recording and reproducing apparatus and a magnetic recording and reproducing apparatus employing such a pole base assembly.The pole base assembly is improved in construction to reduce the manufacturing costs and steps for the magnetic recording and reproducing apparatus and realizing the miniaturization of the magnetic recording and reproducing apparatus.  
      In order to achieve the above-mentioned object, a pole base assembly for a magnetic recording and reproducing apparatus includes a base member provided on a deck adapted to be moved toward the head drum at the time of loading the magnetic tape. A pole member is secured to the top surface of the base member and guides the magnetic tape to angularly run in a section where the magnetic tape contacts the head drum. A top edge guide member is disposed at the top end of the pole member and has a flange adapted to contact the top edge of the magnetic tape when the magnetic tape is running while in contact with the pole member and is moving toward the top end of the pole member.  
      With this arrangement, the pole member may guide the upward and downward movement of the magnetic tape in place of a conventional guide roller, whereby the manufacturing costs and steps for a magnetic recording and reproducing apparatus may be reduced. In addition, such a magnetic recording and reproducing apparatus may be easily miniaturized.  
      According to a preferred embodiment, it is preferable that the pole member is angularly connected to the top surface of the base member in such a way that the circumferential surface of the pole member contacting the magnetic tape is parallel to the rotational axis of the head drum when the loading of the magnetic tape has been completed. Preferably, the flange of the top edge guide member is formed to be slanted in relation to the circumferential surface of the pole member in such a way that the flange is parallel to the running direction of the magnetic tape in the section where the magnetic tape and the head drum are in contact with each other.  
      The top edge guide member preferably has a posture maintaining means to substantially prevent the pole member from being rotated in relation to the top edge guide member. The posture retaining means includes a guide pin extending from one side of the top edge guide member and a guide projection extending from the base member by a predetermined height and connected with the guide pin to prevent the top edge guide member from being rotated in relation to the pole member.  
      Preferably, the guide pin and the guide projection are slidably engaged in a direction parallel to the main axial direction of the pole member.  
      Preferably, the pole member has a threaded part formed at the bottom end thereof to be threaded into a fixing hole formed in the top surface of the base memberand the threaded part is subjected to anti-release treatment. The fixing hole has female threads formed on the internal surface of the fixing hole is cut by the male-threads of the threaded part when F the threaded part is press-fitted into the fixing hole.  
      In addition, a fixing projection and a fixing slot are formed at the bottom end of the thread part and the fixing hole, respectively, in such a way that they are press-fitted with each other when the threaded part is threaded into the fixing hole.  
      With this arrangement, the slant angle and the height of the pole member may be easily adjusted at the time of connecting the pole member and the base member.  
      Preferably, a bottom edge guide member is integrally formed on the base member, which comes into contact with the bottom edge of the magnetic tape when the magnetic tape contacts the pole member as the magnetic tape moves toward the bottom end of the pole member.  
      Preferably, the bottom edge guide member and the base member are integrally formed as a molded product of synthetic resin.  
      Furthermore, the top surface of the bottom edge guide member preferably forms an obtuse angle with the circumferential surface of the pole member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The above and other objects and features of the present invention will be more apparent from the description for certain embodiments of the present invention taken with reference to the accompanying drawings, in which:  
       FIG. 1  is a top plan view schematically showing the interior of a conventional deck of a magnetic recording and reproducing apparatus;  
       FIG. 2  is a perspective view showing the operating state of the pole base assembly of  FIG. 1 ;  
       FIG. 3  is a perspective view of the interior of a deck according to a first embodiment of the present invention;  
       FIG. 4  is an exploded perspective view of the pole base assembly extracted from  FIG. 3 ;  
       FIG. 5  is a partially exploded side view of the pole base assembly of  FIG. 3 ;  
       FIG. 6  is a schematic view of of the pole base assembly of  FIG. 3  extracted along the running direction of the magnetic tape; and  
       FIG. 7  is an exploded perspective view of a pole base assembly according to another embodiment of the present invention. 
    
    
      Throughout the drawings, like reference numbers will be understood to refer to like parts, components and structures.  
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       FIG. 3  is a perspective view of the interior of a deck according to a first embodiment of the present invention. Referring to  FIG. 3 , a deck  200  of a magnetic recording and reproducing apparatus according to a preferred embodiment of the present invention includes a deck chassis  10  and pole base assemblies  350  and  350 ′ 
      The pole base assemblies  350  and  350 ′ draw a magnetic tape  1  (refer to  FIG. 6 ) out of a tape cassette  90  at the time of loading the magnetic tape  1  to bring the magnetic tape  1  into close contact with the head drum and to guide the magnetic tape  1  to run in close contact with the head drum. Pole base assemblies  350  and  350 ′ are installed as a pair on the deck chassis  10  to correspond to the left and right sides of the head drum  30 . In general, the pole base assembly for guiding the magnetic tape  1  entering into the head drum  30  is called a “supply side pole base assembly”  350  and the pole base assembly for guiding the magnetic tape  1  discharged from the head drum  30  is called a “winding side pole base assembly”  350 ′. Although the present invention is applicable to both of the pair of the pole base assemblies  350  and  350 ′, the present invention is described with regard to the supply side pole base assembly  350  only for matters of convenience.  
      As shown in FIGS.  4  to  6 , the supply side pole base assembly  350  includes a base assembly  351 , a pole member  353 , a first guide member  355 , and a second guide member  357 .  
      The base member  351  is moved to a loading position PI (see  FIG. 1 ) adjacent to the head drum at the time of loading the magnetic tape  1 , and the base member  351  is moved to an unloading position P 2  (see  FIG. 1 ) at the time of unloading the magnetic tape  1 . Such movement of the base member  351  is provided by a loading motor  20  ( FIG. 3 ) and a connecting unit (not shown) installed on the deck to transfer the power of the loading motor to the base member  351 . Because the specific construction of the loading motor  20  and the connecting unit are well-known in the art, the detailed description thereof is omitted. Meanwhile, reference numeral  354  indicates a fixing hole into which threads  356  formed on the bottom end of a pole member  353  are engaged for connecting the pole member  353  and the base member  351 . In addition, reference numeral  352  indicates a guide projection slidably connected with a guide pin  357   a  to be described later.  
      The pole member  353  is secured to the top surface of the base member  351  and moved with the base member  351  at the time of loading the magnetic tape  1  (see  FIG. 6 ) to urge the magnetic tape  1  to come into close contact with the head drum  30 . When the magnetic tape I runs after the completion of the loading of the magnetic tape, the pole member  353  guides the magnetic tape  1  to run in close contact with the head drum  30 .  
      The pole member  353  according to the present embodiment is angularly secured to the top surface of the base member  351 . This is because the head drum  30  is angularly installed on the deck chassis  10 . The running posture of the magnetic tape  1  in a section B (refer to  FIG. 2 ) where the magnetic tape  1  is contacted with the head drum  30  is angled with respect to the running posture thereof in other sections. Thus, the pole member  353  is preferably installed to be angled with respect to the bottom surface of the deck chassis  10  so that the circumferential surface is parallel to the parts of the circumferential surface of the head drum  30  where the contact between the magnetic tape  1  and the head drum  30  is initiated and terminated. The magnitude of the angle formed between the pole member  353  and the base member  351  may be varied according to the shape of the guide rail  11  (see  FIG. 3 ) for guiding the movement of the base member  351  at the time of loading and unloading of the magnetic tape  1 . Although not shown in the drawings, if the base member  351  is angularly guided to correspond to the circumferential surface of the head drum  30  by the guide rail  11  at the time of loading the magnetic tape  1 , preferably, the pole member  353  and the base member  351  are substantially perpendicular to one another. If the base member  351  is moved parallel to the bottom surface of the deck chassis  10  at the time of loading and unloading of the magnetic tape  1 , the pole member  353  is installed on the base member  351  forming an angle θ between the circumferential surface of the head drum  30  and the deck chassis  10 , as shown in  FIG. 5 .  
      In order to angularly connect the pole member  353  on the base member  351 , the pole base assembly  350  according to the present embodiment includes a threaded part  356  formed at the bottom end of the pole member  353  and a fixing hole  354  formed in the base member  351 . The threaded part  356  is formed in a taptite shape subjected to anti-release treatment. In addition, the male threads of the threads part  356  form female threads on the internal circumferential surface of the fixing hole  354  by cutting the internal circumferential surface of the fixing hole  354  when the threaded part  356  press-fitted into the fixing hole  354 . For this purpose, it is preferred that the inner diameter D 2  of the fixing hole  354  is somewhat smaller than the outer diameter D 1  of the threaded part  356 . With the screw connection between the threaded part  356  and the fixing hole  354 , it is easy to set the height of the pole member  353  with reference to the base member  351 . In addition, because the threaded part  356  is formed in the taptite shape, it is possible to prevent the threaded part from being reversely rotated due to an external impact or vibration, thereby preventing variation of the height of the pole member  353 . Meanwhile, according to the present embodiment, a fixing projection  356 a is extended from the bottom end of the threaded part  356 , and the bottom surface of the fixing hole  354  is additionally formed with a fixing slot  354   a  (see  FIG. 5 ). The fixing projection  356   a  and the fixing slot  354   a  guide the threaded part  356  and the fixing hole  354  at the time of fitting the threaded part  356  into the fixing hole  354  so that the angle of the pole member  353  and the base member  351  may be correctly set. Preferably, the outer diameter D 3  of the fixing projection  356   a  is formed to be somewhat larger than the inner diameter D 4  of the fixing slot  354   a  so that an interference fit is formed between the fixing projection and the fixing slot prior to the threaded part  356  and the fixing hole  354  being engaged with each other. Therefore, the angle between the pole member  353  and the base member  351 , as well as the height of the pole member  353  with reference to the base member  351 , may be correctly set at the time of connecting the pole member  353  and the base member  351 . To facilitate the connection of the threaded part  356  and the fixing hole  354 , preferablythe base member  351  is formed as a molded product of synthetic resin. Since a small amount of force is required to connect the fixing hole  354  and the threaded part  356 , the adjustment of the height and slant angle may be manually performed with ease by an operator.  
      The pole base assembly  350  includes first and second guide members  355  and  357  to eliminate the conventional guide roller  55  (see  FIG. 1 ). With the first and second guide members  355  and  357 , it is possible to prevent the magnetic tape  1  from being moved along the direction parallel to the rotational axis of the head drum  30 . As a result, it is possible to omit the conventional guide roller  55  (see  FIG. 1 ).  
      The first guide member  355  is integrally formed on the top surface of the base member  351  and comes into contact with the bottom edge of the magnetic tape  1  when the magnetic tape  1  is moved toward the bottom end of the pole member  353 . The first guide member  355  and the base member  351  are preferably formed as molded products of synthetic resin so that the first guide member  355  and the base member  351  may easily be integrally formed with each other. In addition, it is preferable that the first guide member  355  and the circumferential surface of the pole member  353  form an obtuse angle therebetween. Considering the guiding of the bottom edge of the magnetic tape  1 , preferably the angle formed between the first guide member  355  and the circumferential surface of the pole member  353  is about 90 degrees to 130 degrees. With this arrangement, the magnetic tape  1  returns to the center of the pole member  353 , thereby avoiding damaging the magnetic tape.  
      A part of the top surface of the base member  351  adjacent to the bottom end of the pole member  353  is used as the first guide member  355 . The guide rail  11  is formed parallel to the reference surface H (see  FIG. 6 ), so that the base member  351  is moved parallel to the deck chassis  10 . The pole member  353  is angularly connected to the base member  351 . The pole member  353  is capable of always retaining an angled position in relation to the deck chassis  353  as shown in  FIG. 3  at the time of loading, unloading and running of the magnetic tape  1 , so that the magnetic tape  1  tends to move only toward the top of the pole member  353  at the time of loading, unloading and running of the magnetic tape  1 . If the pole base assembly  350  and the guide rail  11  are formed in such a way that the pole member  353  cannot retain the angled position in relation to the deck chassis in at least a section of its course, the first guide member  355 ′ preferably extends to a predetermined height from the base member  351 ′ of the pole base assembly  350 ″ according to a second embodiment of the present invention, as shown in  FIG. 7 . In this event, the guide member  355 ′ may be formed in various suitable forms without being limited to the form shown in the drawingto prevent the downward movement of the magnetic tape  1 .  
      The second guide member  357  is provided at the top end of the pole member  357  and is provided with a flange  358  adapted to contactthe top edge of the magnetic tape  1  as it moves toward the top end of the pole member  353 . Here, the flange  358  of the second guide member  357  is formed parallel to the running direction of the magnetic tape  1  in the section B (see  FIG. 2 ) where the head drum  30  and the magnetic tape  1  are in contact with each other. Preferably, the flange  358  of the second guide member  357  is formed at an angle in relation to the circumferential surface of the pole member  353 . However, it is not necessary to form the bottom surface of the flange  353  to be entirely slanted. That is, as shown in  FIG. 5 , it is sufficient if only a part corresponding to a section of the pole member  353  contacts the magnetic tape  1  at the time of loading, unloading and running of the magnetic tape  1  is angularly formed. The remaining part except the angularly formed part may be formed in various forms only if it does not cause any problems at the time of running of the magnetic tape  1  and in configuring the deck  200 .  
      The second guide member  357  as described above is secured to the top end of the pole member by press-fitting the pole member  353  into the connecting hole  357   c  formed at the center of the second guide member  357 . In addition, the second guide member  357  is enclosed by the cover member  359  at its top endto prevent the second guide member from breaking away from an upper part of the pole member  353 .  
      Since the second guide member  357  and the pole member  353  are connected with each other, the pole base assembly  350  according to the present embodiment further comprises a posture retaining means to prevent the second guide member  357  from being rotated in relation to the pole member  353 . The posture retaining means prevents the magnetic tape  1  from being incorrectly guided as the flange  353  formed to be angled in relation to the pole member  353  is rotated at the tope end of the pole member  353  The posture retaining means includes a guide pin  357   a  and a guide projection  352 . A guide slit  357   b  is formed at the tip end of the guide pin  357   a , and the guide slit  357   b  is slidably connected with the guide projection  352  extending from the base member  351 . With this arrangement, the guide slit  357   b  and the guide projection  352  are substantially prevented from being separated from each other even when the height is varied by adjusting the thread connection between the threaded part  356  and the fixing hole  354 .  
      In the above, the present invention has been described only in terms of the supply side pole base assembly  350  among a pair of pole base assemblies  350  and  350 ′. However, because the winding side pole base assembly  350 ′ is substantially similar to the supply side pole base assembly  350  in construction, the present invention is also applicable to the winding side pole base assembly  350 ′.  
      In addition, although the present invention has been described with reference to a deck of a camcorder by way of an example, the present invention is also applicable to a deck of a magnetic recording and reproducing apparatus of another type, such as a vide tape recorder (VTR) if such a deck includes a pole base assembly with a pole base and a base member as described above.  
      According to the present invention as described above, the first and second guide members  355 ,  355 ′ and  357  are provided at the top and bottom ends of the pole member  353  of the pole base assemblies  350 ,  350 ′ and  350 ″, respectively, to guide the upward and downward movement of the magnetic tape. Accordingly, it is not required to provide a separate member, such as a conventional guide roller  55  (refer to  FIG. 1 ) to align the top and bottom positions of the tape. In addition, because the second guide members  355  and  355 ′ are integrally formed on the base members  351  and  351 ′, the base member  351 ,  351 ′ and the second guide member  355  and  355 ′ can be more easily formed. As a result, a magnetic recording and reproducing apparatus may be easily miniaturized as well reducing the manufacturing costs and steps for a magnetic recording and reproducing apparatus can be reduced.  
      While the preferred embodiments of the present invention have been shown and described in order to exemplify the principle of the present invention, the present invention is not limited to the specific embodiments. It will be understood that various modifications and changes can be made by one skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, it shall be considered that such modifications, changes and equivalents thereof are all included within the scope of the present invention.