Abstract:
Disclosed is a reel clutch of a tape recorder. A plate spring is positioned between a reel gear and a reel disc of a reel disc assembly which is mounted on a deck of a tape recorder, and a stopper reel is provided on the reel disc to restrain the engaging height of the plate spring so that a torque is generated by the frictional contact between the reel disc and the plate spring, whereby assembly productivity can be enhanced and manufacturing costs can be reduced.

Description:
FOREIGN PRIORITY INFORMATION  
         [0001]    This application claims priority under 35 U.S.C. §119 to a Korean Patent Application, Serial No. 2002-61821, filed in the Korean Intellectual Property Office on Oct. 10, 2002, to Korean Patent Application Serial No. 2002-68836, filed in the Korean Intellectual Property Office on Nov. 7, 2002, to Korean Patent Application Serial No. 2002-71728, filed in the Korean Intellectual Property Office on Nov. 18, 2002, and to Korean Patent Application Serial No. 2003-3426, filed in the Korean Intellectual Property Office on Jan. 17, 2003, the contents of all four said applications being incorporated herein by reference  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to a magnetic recording/reproducing apparatus, and more particularly, to a reel apparatus for driving a tape cassette of a magnetic recording/reproducing apparatus.  
           [0004]    2. Description of the Related Art  
           [0005]    Generally, a magnetic recording/reproducing apparatus records information on a recording medium such as a magnetic tape, and also reproduces the recorded information from the recording medium. Examples of such magnetic recording/reproducing apparatuses mainly include video tape cassette recorders (VCR) and camcorders.  
           [0006]    Referring to FIG. 1, a conventional magnetic recording/reproducing apparatus includes a main deck  2  on which a head drum  1  is rotatably mounted; a sub deck  3 , which can be loaded/unloaded with respect to the main deck  2 ; a pair of reel assemblies  4 , which are rotatable with respect to the sub deck  3  and drive the tape reel of the tape cassette; a reel assembly driving apparatus  7 , which receives the driving force from a capstan motor  5  at the main deck  1  and selectively transmits the received driving force to the pair of reel assemblies  4 ; and a driving force transmitting unit  6 , which transmits the driving force from the capstan motor  5  to the reel assembly driving apparatus  7 .  
           [0007]    The reel assemblies  4  include a supply part reel table (left-hand side of FIG. 1) to supply magnetic tape from the tape cassette, and a take-up part reel table (right-hand side of FIG. 1) to wind the magnetic tape as fed.  
           [0008]    The driving force transmitting unit  6  includes a capstan gear  6   a , driven in association with an axis gear  5   a  of the capstan motor  5 , and a timing belt  6   b , to transmit the driving force from the capstan gear  61   a  to the reel assembly driving apparatus  7 .  
           [0009]    The reel assembly driving apparatus  7  includes a pulley gear unit  7   a , which is connected with a timing belt  6   b , an idle gear  7   b  driven in association with the pulley gear unit  7   a , and a pivoting plate  7   c  connecting the pulley gear unit  7   a  to the idle gear  7   b.    
           [0010]    As shown in FIG. 2, the pivoting plate  7   c  may have an elastic part  7   d  which is cut in a predetermined pattern in the central portion of the pivoting plate  7   c  so as to function as a plate spring. Because the elastic part  7   d  is contacted with the idle gear  7   b  with a predetermined frictional force, when the idle gear  7   b  shifts the direction of its rotation, the pivoting plate  7   c  is subjected to a torque which causes the pivoting plate  7   c  to pivot. Accordingly, the idle gear  7   b  can be selectively connected to the left and right reel assemblies  4 .  
           [0011]    In the above-described construction, a part of rotational force of the pulley gear  11  is transmitted to a clutch gear  13  by the magnetic force generated between a magnet  12  and a metal piece  14 . Since the rotational force can be reduced as the force is transmitted via the idle gear  7   b  to the destined reel assembly  4 , the tape reel of the tape cassette can be rotated with the correct force.  
           [0012]    However, in the conventional magnetic recording/reproducing apparatus constructed as above, because some components are required to provide a predetermined frictional force to the idle gear  7   b  to pivot the pivoting plate  7   c , the overall construction becomes complicated. Further, as additional components are also required to control the torque to the tape cassette reel, the construction of the magnetic recording/reproducing apparatus becomes still more complicated. Also, because the price of the magnet employed in the conventional magnetic recording/reproducing apparatus is usually high, the manufacturing costs increase.  
           [0013]    Alternatively, a frictional force generator, i.e., a torque generator as provided to the pulley gear unit  7   a , can also be provided to the pair of reel assemblies  4  as a substitute. However, the problem is that this substitute also requires expensive components of rather complicated structure.  
         SUMMARY OF THE INVENTION  
         [0014]    Accordingly, it is an aspect of an embodiment of the present invention to provide a reel assembly driving apparatus and a reel assembly of a magnetic recording/reproducing apparatus, which is improved to have a simple construction.  
           [0015]    In order to achieve the above aspect, the preferred embodiment of the present invention provides a reel clutch of a tape recorder, which is installed in a reel disc assembly mounted on a deck of a tape recorder and having a reel gear and a reel disc, for generating a torque to adjust the tension of a magnetic tape, thereby controlling the running speed of the magnetic tape. the reel clutch comprises a plate spring positioned between the reel gear and the reel disc; and a stopper reel engaged with the reel disc to restrain the engaging height of the plate spring, so that the reel disc and the plate spring come into contact with each other to generate a torque by friction.  
           [0016]    In the reel clutch having the above-described construction according to an embodiment of the present invention, the bottom surface of the reel disc is preferably provided with serrations which are formed to be capable of coming into frictional contact with the plate spring.  
           [0017]    In addition, it is preferable that the plate spring comprises a plate body which is formed with one or more slits in a predetermined pattern, so that the plate spring is elastically freely movable by an external pressure.  
           [0018]    Furthermore, it is preferable that a lubricant is interposed between the reel disc and the plate spring. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    The above and other aspects, features and advantages of the present invention will be more apparent from the following detailed description taken with reference to the accompanying drawings, in which:  
         [0020]    [0020]FIG. 1 is a schematic plan view illustrating a conventional magnetic recording/reproducing apparatus;  
         [0021]    [0021]FIG. 2 is a sectional view illustrating the reel assembly driving apparatus of FIG. 1;  
         [0022]    [0022]FIG. 3 is a perspective view illustrating an assembly of a magnetic recording/reproducing apparatus according to a preferred embodiment of the present invention before assembling;  
         [0023]    [0023]FIG. 4 is a sectional view illustrating the assembly of the magnetic recording/reproducing apparatus according to the preferred embodiment of the present invention after assembling;  
         [0024]    [0024]FIG. 5 is a perspective view illustrating an upper reel of FIG. 3;  
         [0025]    [0025]FIG. 6 is a sectional view illustrating a reel assembly according to another preferred embodiment of the present invention;  
         [0026]    [0026]FIG. 7 is a perspective view of the reel gear of FIG. 6; and  
         [0027]    [0027]FIG. 8 is a sectional view illustrating a reel assembly driving apparatus of a magnetic recording/reproducing apparatus according to yet another preferred embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]    A reel assembly and a reel assembly driving apparatus of the magnetic recording/reproducing apparatus according to an embodiment of the present invention will now be described in greater detail with reference to the accompanying drawings and the preferred embodiments of the present invention.  
         [0029]    Referring to FIGS. 3 and 4, the reel assembly of the magnetic recording/reproducing apparatus according to one preferred embodiment of the present invention includes a lower reel  31  rotatable with respect to a stationed axis  2   a  at the main deck  2 , an upper reel  33  (or reel disc) joined with the upper portion of the lower reel  31  (or stopper reel), and a clutch member  37  disposed between the lower and upper reels  31 ,  33 .  
         [0030]    The lower reel  31  has an axis portion  31   b  protruding from the center of a circular body  31   a  to a predetermined height. The stationed axis  2   a  is fit with respect to the axis portion  31   b.  Around the lower portion of the axis portion  31   b  and on the upper surface of the circular body  31   a  is formed a protruding part  31   c  formed with a predetermined height. There is formed an axis hole  33   a  in the lower surface of the upper reel  33  so that the axis portion  31   b  is inserted in the axis hole  33   a  of the upper reel  33  to a predetermined depth. The axis portion  31   b  is force-fit in the axis hole  33   a  so as to cause a frictional force with the axis hole  33   a . Accordingly, the upper and lower reels  31 ,  33  are rotated altogether.  
         [0031]    The upper portion of the upper reel  33  is protruded in a predetermined shape so that the tape reel of the tape cassette is securely seated thereon. Around the lower surface of the upper reel  33 , there is formed an annular rib  33   b  which is protruded to elastically urge the outer rim of the clutch member  37  downward. Also, as shown in FIG. 5, a serration is formed on the surface of the rib  33   b  with a predetermined roughness. The serration is formed along the surface of the rib  33   b  in an annular fashion.  
         [0032]    The reel gear  35  is disposed between the upper and lower reels  31 ,  33 . The reel gear  35  has an annular shape, and is provided with gear teeth  35   a  formed along the outer circumference. The gear teeth  35   a  are selectively connected to the idle gear  7   b  (FIG. 1) of the driving apparatus which is driven by the driving force from the capstan motor  5  to receive the driving force. The clutch member  37  is fit in the reel gear  35 , and in order to secure the clutch member  37  in position, there are locking protrusions  35   b  formed along the inner circumference of the reel gear  35 . The locking protrusions  35   b  are elongated in the direction along which the clutch member  37  is fit into the reel gear  35 , and also provided at regular intervals. The reel gear  35  is connected to the upper and lower reels  31 ,  33  by the intervention of the clutch member  37 . In other words, the reel gear  35  is connected such that the reel gear  35  is not directly contacted with the upper and lower reels  31 ,  33 .  
         [0033]    The clutch member  37  functions to reduce the rotational force of the reel gear  35  and transmit the reduced rotational force to the upper and lower reels  31 ,  33 . It is preferable that the clutch member  37  is a plate spring. There is an axis hole  37   a  into which the axis portion  31   b  is inserted. The clutch member  37  also has slits  37   b  which are cut in a predetermined fashion to enable the clutch member  37  to elastically move in the vertical direction freely by the external force. The clutch member  37  also has a plurality of locking holes  37   c  formed in the outer circumference to correspond to the locking protrusions  35   b . The clutch member  37  also has a plurality of fitting holes  37   d  to fit with hooks  35   c  of the reel gear  35 . The clutch member  37  supported on the reel gear  35  is contacted with, and thus supported by, the upper and lower reels  31 ,  33 , respectively.  
         [0034]    The center of the clutch member  37  is contacted with the protruding part  31   c  of the lower reel  31  and thus elastically urged upward. The outer rim of the clutch member  37  is elastically urged downward by the contact with the rib  33   b  of the upper reel  33 . Due to the contact between the clutch member  37  and the upper and lower reels  31 ,  33 , the rotational force of the reel gear  35  is transmitted to the upper and lower reels  31 ,  33 . Here, the rotational force is not entirely transmitted to the upper and lower reels  31 ,  33 , but transmitted in a reduced degree in accordance with the degree of frictional force which is caused by the clutch member  37 .  
         [0035]    Preferably, a lubricant (not shown) is applied between the upper reel  33  and the clutch member  37 . More preferably, the lubricant (not shown) is applied to the lower surface of the upper reel  33  and the upper surface of the clutch member  37  at the point where the annular ribs  33   b  contact the outer rim of the clutch member  37 .  
         [0036]    In the reel assembly of the magnetic recording/reproducing apparatus constructed as above according to the first preferred embodiment of the present invention, the elastic clutch member  37  is firmly secured to the reel gear  35  and does not sway or move. Further, because the clutch member  37  is positioned at an accurate height by the support of the upper and lower reels  31 ,  33 , the resiliency of the clutch member  37  seldom varies, and therefore, the frictional force with the neighboring components can be maintained substantially constant. As a result, the driving force from the reel gear  35  to the upper and lower reels  31 ,  33  can be maintained to a substantially constant degree. Additionally, because the reel assembly has a simple structure and does not require an expensive magnet, manufacturing costs can be reduced.  
         [0037]    Referring now to FIGS. 6 and 7, a reel assembly of a magnetic recording/reproducing apparatus according to a second preferred embodiment of the present invention will be described. Throughout the description, like elements will be given the same reference numerals of FIGS.  3  to  5 .  
         [0038]    Shown in FIGS. 6 and 7, there is a sensor, i.e., a light receiving/emitting sensor  40 , to sense the rotational status of the reel gear  135  with respect to the sub deck  3 . As described above, the reel gear  135  has gear teeth  125   a  which are engaged with the idle gear  7   b  (FIG. 1) of the reel assembly driving apparatus. The driving force, which is transmitted to the reel gear  135  via the idle gear  7   b , generates a torque with the intervention of the clutch member  37  so as to cause the upper reel  33  to rotate at a predetermined speed.  
         [0039]    Meanwhile, the reel gear  135  has a plurality of sensing holes  135   c  formed in the direction of rotation. The sensing holes  135   c  are pierced so that the light from the light receiving/emitting sensor  40  can pass therethrough. As shown in FIG. 7, the sensing holes  135   c  are formed at equal intervals in the direction of rotation of the reel gear  135 .  
         [0040]    In the above-mentioned construction, the light receiving/emitting sensor  40  emits a light toward the reel gear  135 , and also receives the light reflected from the reel gear  135  so as to sense the rotational status and the speed of the reel gear  135 . Because the light is reflected from the reel gear  135  except where the sensing holes  135   c  occur, the light receiving/emitting sensor  40  can determine the rotational status of the reel gear  135  through repetitive reception and non-reception of the light reflected from the reel gear  135 . When the reel gear  135  is not rotated, the light receiving/emitting sensor  40  may successively receive the light or may not receive the light at all, thus recognizing that the reel gear  135  is not rotating. The reel gear  135  is preferably made of white material which can reflect the light effectively, although other colors can also be adequately used.  
         [0041]    With the reel assembly described as above, the reel assembly can be constructed without requiring additional components, by simply attaching a reflective film to some parts of the reel gear  135  to reflect the light, or by forming the sensing holes  135   c  instead of attaching additional light absorbent material.  
         [0042]    Referring to FIG. 8, the reel assembly driving apparatus according to a third preferred embodiment of the present invention will be described. As shown in FIG. 8, the reel assembly driving apparatus includes a main gear  50  which is rotatable with respect to the main deck  2 , a rotating lever  60  which is rotatable with respect to the upper portion of the main gear  50 , an idle gear  70  engaged with the main gear  50 , a clutch gear  80  arranged coaxially with the idle gear  70 , a rotating body  90  rotatably supported on the rotating lever  60 , and an elastic clutch member  100 .  
         [0043]    The main gear  50  is rotatably supported on the stationed axis  2   a  of the main deck  2  so as to be rotated by the driving force transmitted from the capstan motor  5  (FIG. 1). A pulley part  53 , being connected with the timing belt  6   b , is provided to the lower end of the main gear  50 . Gear part  55  is engaged with the idle gear  50  to the upper portion of the pulley part  53 . There is a damper  57  at the upper portion of the axis  2   a  to prevent the main gear  50  from separating from the axis  2   a.    
         [0044]    One end of the rotating lever  60  is supported by the damper  57 , while there is a fixed axis  61  formed at the other end of the rotating lever  60 . The fixed axis  61  is provided at the lower portion of the rotating lever  60 . As shown in FIG. 1, the rotating lever  60  is rotated to selectively connect to the pair of reel assemblies  4 . The rotating force of the rotating lever  60  is transmitted from the main gear  50  to the idle gear  70 , the clutch member  100  and the rotating body  90 , respectively. When there is a frictional force between the rotating body  90  and the rotating lever  60 , the rotating torque is generated at the rotating lever  60  to cause the rotating lever  60  to rotate.  
         [0045]    The idle gear  70  has a gear part  71  which is engaged with the main gear  50 . The idle gear  70  is rotatably engaged with the outer circumference of the rotating body  90 . The idle gear  70  has an upper flange  73  which exclusively presses the outer rim of the clutch member  100  by the contact while being secured in a movement restriction protrusion  91  formed on the lower end of the rotating body  90 . Due to the friction between the upper flange  73  and the contacting area of the clutch member  100 , a torque is generated, and the clutch gear  80  is rotated by the generated torque.  
         [0046]    The clutch gear  80  is engaged to one of the pair of reel assemblies  4  to transmit the driving force. The clutch gear  80  is secured to the outer side of the clutch member  100 .  
         [0047]    The rotating body  90  is rotatable with respect to the fixed axis  61 , and is supported such that the rotating body  90  can be moved vertically. The rotating body  90  also has a locking groove  93  into which the clutch member  100  is securely fit in with the inner circle. The rotating body  90  is subjected to a force in the ‘A’ direction due to the elastic recovery force of the clutch member  100 , and thus, urged to maintain a contact with the rotating lever  60  at an upper part with a predetermined friction. The rotating body  90  is integrally rotated with the clutch member  100 .  
         [0048]    Clutch member  100  is provided to adjust the rotational speed of the reel assemblies  4  by preventing direct transmission of the driving force from the main gear  50  to the reel assemblies  4  without any adjustments. The clutch member  100  functions to reduce the driving force from the main gear  50  before transmitting it to the reel assemblies. It is preferable that the clutch member  100  is a plate spring which is deformable and recoverable. The clutch member  100  is secured at its outer part to the clutch gear  80 , and more preferably, the clutch member  100  is integrally secured to the clutch gear  80  by an insert molding. The center of the clutch member  100  is securely locked in the locking groove  93  of the rotating body  90 . As the clutch member  100  is pressed toward the idle gear  73 , the rim of the clutch member  100  is subjected to the elastic recovery force in the ‘B’ direction, while the center of the clutch member  100  is subjected to the elastic recovery force in the ‘A’ direction. As a result, at the contact area between the clutch member  100  and the idle gear  70 , a ‘clutching effect’ can be obtained. In other words, the driving force is decreasingly adjusted before being transmitted. Further, due to the elastic recovery force in the ‘A’ direction, the rotating body  90  and the rotating lever  60  are integrally rotated with respect to the main gear  50 .  
         [0049]    In the reel assembly driving apparatus according to the present invention as described above, a single clutch member  100 , i.e., a single plate spring, not only serves as a clutch to adjust the driving force which is transmitted from the main gear  50 ,to the reel assemblies  4 , but also serves as a torque generator which enables the rotating lever  60  to shift the rotating direction. Accordingly, expensive component such as a magnet can be omitted, and two torques can be obtained in the same area. As a result, as the number of necessary parts decreases, and the assembling process is simplified, manufacturing costs can be greatly reduced.  
         [0050]    While a few preferred embodiments of the present invention has been shown and described with reference to the preferred embodiments thereof, the present invention is not limited to those embodiments. It will be understood by those skilled in the art that various modifications and 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.