Abstract:
The present invention relates to a portable book holder that can be converted from its original size into a small size if a user wants to carry the portable book holder, thereby making it easy to be carried, adjust a supporting area in accordance with the sizes of a book, and allow a user to adjust a book holding stand to his or her desired arbitrary angle.

Description:
REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of pending International Patent Application PCT/KR2012/001635 filed on Mar. 6, 2012, which designates the United States and claims priority of Korean Patent Application No. 10-2011-0027320 filed on Mar. 28, 2011, the entire contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a portable book holder that can be converted from its original size into a small size if a user wants to carry the portable book holder, thereby making it easy to be carried, adjust a supporting area in accordance with the sizes of a book, and allow a user to adjust a book holding stand to his or her desired arbitrary angle. 
     BACKGROUND OF THE INVENTION 
     Generally, a book holder is designed to maintain a book to the same height as a user&#39;s eyes, while having an appropriate distance from the book, and thus, the book holder has a plurality of locking protrusions formed on the bottom surface thereof so as to adjust the inclination of the book. 
       FIG. 1  is a perspective view showing a conventional book holder. The conventional book holder includes a book holding stand  10  for supporting the underside surface of a book, a locking member  20  mounted on the rear side of the book holding stand  10 , and a supporting stand  30  having locking protrusions  35  onto which the locking member  20  is fixedly locked formed thereon so as to adjust the angle of the book holding stand  10 . 
     Under the above-mentioned configuration, however, the conventional book holder is inconvenient to be carried due its fixed size, and accordingly, if a large or small-sized book is located on the book holding stand, it may be not supported thereon well. Especially, the book holding stand is adjusted only to the fixed angles, thereby making it impossible to conduct the angle adjustment thereof to a user&#39;s desired arbitrary angle. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention has been made in view of the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a portable book holder that can be converted from its original size into a small size if a user wants to carry the portable book holder, thereby making it easy to be carried, adjust a supporting area in accordance with the sizes of a book, and allow a user to adjust a book holding stand to his or her desired arbitrary angle. 
     To accomplish the above object, according to the present invention, there is provided a portable book holder including: a body having long grooves formed along the left and light sides thereof; a screw shaft rotatably mounted inside the body and having a right-handed screw and a left-handed screw formed symmetrically on the front and rear outer peripheries thereof; a front nut and a rear nut coupled correspondingly to the front side right-handed screw and the rear side left-handed screw and moved in the forward and backward directions of the screw shaft in such a manner as to be distant from or adjacent to each other in accordance with the rotation of the screw shaft; a book holding stand hinge-coupled to the front nut on the front end thereof and having a plurality of left and right supporting members extended and contracted in a telescoping manner in the left and right directions from the inside thereof so as to support the underside surface of the book and a folding type bottom supporting member disposed on the top surface of the front end thereof so as to support the bottom end of the book; an angle adjusting member hinge-coupled to the rear nut on one end thereof and rotatably coupled to the underside surface of the book holding stand on the other end thereof so as to adjust the angle of the book holding stand through the forward and backward movements of the front nut and the rear nut in accordance with the rotation of the screw shaft; and a cover having long coupling protrusions formed along the inner surfaces of the left and right sides thereof in such a manner as to be slidingly inserted into the long grooves of the body and coupled to the body to cover the top surface of the book holding stand. 
     According to the present invention, preferably, each of the front nut and the rear nut has a guide wheel contacted rotatably with the downwardly-recessed upper surface of the body upon the movement in the forward and backward directions of the screw shaft. 
     According to the present invention, preferably, the portable book holder further includes an auxiliary book holding stand coupled to the rear end portion of the book holding stand in such a manner as to be slidingly moved forwardly and backwardly. 
     According to the present invention, preferably, the auxiliary book holding stand has an auxiliary left and right supporting member extended and contracted in a telescoping manner in the left and right directions from the inside thereof so as to support the underside surface of the book. 
     According to the present invention, preferably, the portable book holder further includes: a pair of auxiliary left and right side bottom supporting members rotatably coupled to the left and right sides of the bottom supporting member on one end thereof and turned on the other end thereof in such a manner as to be extended in left and right directions of the bottom supporting member; and a pair of left and right fixing protrusions formed on the top surfaces of the other end of the pair of auxiliary left and right side bottom supporting members so as to fix both side bottom ends of the open book, so that the open state of the book supported by means of the book holding stand is maintained. 
     According to the present invention, preferably, the portable book holder further includes a handle coupled to the front end of the screw shaft by means of a bevel gear. 
     According to the present invention, preferably, the portable book holder further includes a plurality of fixing legs rotatably coupled to the left and right sides of the underside surface of the body on one end thereof and turned on the other end thereof in such a manner as to be exposed from the body. 
     According to the present invention, preferably, the portable book holder further includes a pencil case in which writing instruments are accommodated coupled to the top surface of the cover. 
     According to the present invention, the portable book holder can be converted from its original size into a small size if a user wants to carry the portable book holder, thereby making it easy to be carried, adjust a supporting area in accordance with the sizes of a book, and allow a user to adjust the book holding stand to his or her desired arbitrary angle through the formation of the telescoping left and right supporting members, the folding type bottom supporting member, and the cover. 
     Moreover, the portable book holder can substantially extend the supporting area through the auxiliary book holding stand, the left and right supporting members and the auxiliary bottom supporting members, thereby easily supporting even a large-sized book, and also can maintain the open state of the book by means of the fixing protrusions formed on the auxiliary bottom supporting members. 
     Further, the portable book holder can allow the book holding stand to be easily and conveniently adjusted to a user&#39;s desired arbitrary angle through the front nut and the rear nut coupled correspondingly to the screw shaft on which the front side right-handed screw and the rear side left-handed screw are formed. 
     Additionally, the portable book holder further has the pencil case in which writing instruments are accommodated coupled to the top surface of the cover, so that while being used as the pencil case, it can be separated from the pencil case if the user wants to read a book and used as the book holder, thereby providing high portability and many conveniences in use. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing a conventional book holder. 
         FIG. 2  is a perspective view showing a portable book holder according to one embodiment of the present invention. 
         FIG. 3  is a perspective view showing the state where a cover is separated from the portable book holder of  FIG. 2 . 
         FIG. 4  is a perspective view showing the use state of the portable book holder of  FIG. 2 . 
         FIG. 5  is a side sectional view of  FIG. 4 . 
         FIGS. 6 and 7  are perspective views showing a portable book holder according to an alternative embodiment of the present invention. 
         FIGS. 8 and 9  are perspective views showing a portable book holder according to another alternative embodiment of the present invention. 
         FIG. 10  is a perspective view showing a portable book holder according to another alternative embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     According to the present invention, a portable book holder includes: a body having long grooves formed along the left and light sides thereof; a screw shaft rotatably mounted inside the body and having a right-handed screw and a left-handed screw formed symmetrically on the front and rear outer peripheries thereof; a front nut and a rear nut coupled correspondingly to the front side right-handed screw and the rear side left-handed screw and moved in the forward and backward directions of the screw shaft in such a manner as to be distant from or adjacent to each other in accordance with the rotation of the screw shaft; a book holding stand hinge-coupled to the front nut on the front end thereof and having a plurality of left and right supporting members extended and contracted in a telescoping manner in the left and right directions from the inside thereof so as to support the underside of the book and a folding type bottom supporting member disposed on the top surface of the front end thereof so as to support the bottom end of the book; an angle adjusting member hinge-coupled to the rear nut on one end thereof and rotatably coupled to the underside surface of the book holding stand on the other end thereof so as to adjust the angle of the book holding stand through the forward and backward movements of the front nut and the rear nut in accordance with the rotation of the screw shaft; and a cover having long coupling protrusions formed along the inner surfaces of the left and right sides thereof in such a manner as to be slidingly inserted into the long grooves of the body and coupled to the body to cover the top surface of the book holding stand. 
     As shown in  FIGS. 2 to 10 , a portable book holder according to the present invention includes a body  100 , a screw shaft  200 , a front nut  310 , a rear nut  320 , a book holding stand  400 , an angle adjusting member  500  and a cover  600  and further includes an auxiliary book holding stand  700 , a handle  920 , fixing legs  930  and a pencil case  940 . 
     As shown in  FIGS. 2 to 10 , the body  100  takes a shape of a rectangular cuboid to which a variety of parts as will be discussed later are coupled and attached, and accordingly, the body  100  should be firmly made. Further, since the underside of the body  100  is fixedly contacted with a desk or table, the body  100  should have good flatness. As shown in  FIGS. 2 and 3 , the body  100  has long grooves  110  formed along the left and right sides thereof in such a manner as to insert the cover  600  as will be discussed later thereinto. When the book holding stand  400  as will be discussed later is adjusted in angle, while supporting the underside surface of a book through the mutual action among the screw shaft  200 , the front nut  310 , the rear nut  320  and the angle adjusting member  500 , the body  100  becomes a reference surface with respect to the angle variation of the book holding stand  400 . 
     As shown in  FIGS. 4 and 5 , the screw shaft  200  is rotatably mounted inside the body  100  and has a right-handed screw  210  and a left-handed screw  220  formed symmetrically on the front and rear outer peripheries thereof. Also, the front nut  310  and the rear nut  320  are coupled correspondingly to the front side right-handed screw  210  and the rear side left-handed screw  220  and moved in the forward and backward directions of the screw shaft  200  in such a manner as to be distant from or adjacent to each other in accordance with the rotation of the screw shaft  200 . That is, the screw shaft  200  is longitudinally mounted forwardly and backwardly inside the body  100  in such a manner as to be rotatable on both ends thereof and has the front side right-handed screw  210  and the rear side left-handed screw  220  formed symmetrically on the front and rear sides thereof. Accordingly, the front nut  310  coupled to the front side of the screw shaft  200  and the rear nut  320  coupled to the rear side of the screw shaft  200  are moved in the forward and backward directions of the screw shaft  200  in such a manner as to be distant from or adjacent to each other in accordance with the rotation of the screw shaft  200 . The front nut  310  and the rear nut  320  are coupled to the book holding stand  400  and the angle adjusting member  500  as will be discussed later, so that the angle of the book holding stand  400  is adjusted in accordance with the rotation of the screw shaft  200 . On the other hand, the front end of the screw shaft  200  is protruded from the front side of the body  100  so as to rotate the screw shaft  200 , and thus, the front end of the screw shaft  200  is taken directly by a user to rotate the screw shaft  200 . 
     Further, as shown in  FIGS. 2 to 5 , the handle  920  is coupled to the front end of the screw shaft  200  by means of a bevel gear  910 . That is, if a rotary force is transmitted to the bevel gear  910  by easily turning the handle  920  through the user&#39;s manipulation, the screw shaft  200  can be readily rotated through the engagement of the front end of the screw shaft  200  with the bevel gear  910 . 
     As shown in  FIGS. 3 to 5 , the book holding stand  400  is hinge-coupled to the front nut  310  on the front end thereof and has a plurality of left and right supporting members  410  extended and contracted in a telescoping manner in the left and right directions from the inside thereof so as to support the underside of the book and a folding type bottom supporting member  420  disposed on the top surface of the front end thereof so as to support the bottom end of the book. Further, the angle adjusting member  500  is hinge-coupled to the rear nut  320  on one end thereof and rotatably coupled to the underside surface of the book holding stand  400  on the other end thereof, thereby adjusting the angle of the book holding stand  400  through the forward and backward movements of the front nut  310  and the rear nut  320  in accordance with the rotation of the screw shaft  200 . For example, if the screw shaft  200  is forwardly rotated to allow the front nut  310  and the rear nut  320  to be distant from each other, the front end of the book holding stand  400  and one end of the angle adjusting member  500  are distant from each other, and as shown in  FIG. 3 , the angle of the book holding stand  400  becomes small. At this time, when the front nut  310  and the rear nut  320  are spaced apart from each other by a maximum distance, the book holding stand  400  and the angle adjusting member  500  are laid on top of each other in parallel with each other. Contrarily, if the screw shaft  200  is reversely rotated to allow the front nut  310  and the rear nut  320  to be adjacent to each other, the front end of the book holding stand  400  and one end of the angle adjusting member  500  are adjacent to each other, and as shown in  FIGS. 4 and 5 , the angle of the book holding stand  400  becomes large. At this time, when the front nut  310  and the rear nut  320  are adjacent to each other by a maximum distance, the book holding stand  400  and the angle adjusting member  500  are maintained to the largest angle. 
     As shown in  FIGS. 3 to 5 , the book holding stand  400  has the plurality of left and right supporting members  410  extended and contracted in a telescoping manner in the left and right directions from the inside thereof so as to support the underside of the book and the folding type bottom supporting member  420  disposed on the top surface of the front end thereof so as to support the bottom end of the book. The book holding stand  400  takes a shape of a rectangular cuboid having a size smaller than the body  100  and supports the underside surface of the book. The left and right supporting members  410  of the book holding stand  400  are mounted at the interior of the book holding stand  400  in such a manner as to be extended and contracted in a telescoping manner like an antenna in the left and right directions to totally support the left and right parts of the underside surface of the book. When at least three or more left and right supporting members  410  are provided, they can support the underside surface of even a large-sized book. The folding type bottom supporting member  420  is disposed on the top surface of the front end of the book holding stand  400  and supports the bottom end of the book so as to prevent the book from being falling down. At this time, the folding type bottom supporting member  420  is foldably disposed on the top surface of the front end of the book holding stand  400  and further folded to give no interference to the cover  600 . The bottom supporting member  420  is folded to an angle of 90 degrees upon the folding operation so as to more rigidly support the bottom end of the book. That is, the bottom supporting member  420  is made of a folding type hinge rotatable to 90 degrees. 
     As shown in  FIGS. 2 and 3 , the cover  600  has long coupling protrusions  610  formed along the inner surfaces of the left and right sides thereof in such a manner as to be slidingly inserted into the long grooves  110  of the body  100  and coupled to the body  100  to cover the top surface of the book holding stand  400 . That is, the cover  600  is covered in the state where the body  100  and the book holding stand  400  are folded and reduced to a small size, which makes it easy to be carried. On the other hand, as shown in  FIG. 10 , a pencil case  940  in which writing instruments are accommodated is coupled to the top surface of the cover  600 , thereby serving as a given case as well as a writing instrument keeping space. As shown in  FIG. 10 , the pencil case  940  may be a rectangular shape made of the same material as the cover  600 , but it may have a shape of a pouch. 
     As shown in  FIG. 4 , the fixing legs  930  are rotatably coupled to the left and right sides of the underside surface of the body  100  on the respective one ends thereof and turned on the other ends thereof in such a manner as to be exposed from the body  100 . In the state where only the underside surface of the body  100  is tightly contacted fixedly with a desk, if a book is located on the book holding stand  400 , the book holding stand  400  may be moved due to the weight of the book located thereon. Accordingly, the fixing legs  930  are exposed to the left and right sides of the body  100  to support the body  100  over a relatively large area, thereby achieving more rigid fixation. 
     On the other hand, the front nut  310  and the rear nut  320  are moved in the forward and backward directions of the screw shaft  200  in such a manner as to be adjacent to each other or distant from each other in accordance with the rotation of the screw shaft  200 , and if the book is located on the book holding stand  400 , the screw shaft  200  may be bent or deformed due to the weight of the book itself. At this time, when the front nut  310  and the rear nut  320  are moved in the forward and backward directions of the screw shaft  200  bent or deformed, the respective screw threads of the right-handed screw  210  and the left-handed screw  220  do not form regular distances, thereby failing to conduct the smooth movements of the front nut  310  and the rear nut  320 . So as to avoid these problems, as shown in  FIGS. 4 and 5 , each of the front nut  310  and the rear nut  320  has a guide wheel  330  contacted rotatably with the downwardly-recessed upper surface of the body  100  upon the movement in the forward and backward directions of the screw shaft  200 . That is, the guide wheels  330  of the front nut  310  and the rear nut  320  are contacted with the downwardly-recessed upper surface of the body  100 , so that the repulsive force to the weight of the book itself is transmitted to the screw shaft  200  through the guide wheels  330 , thereby preventing the screw shaft  200  from being bent or deformed. Furthermore, the guide wheels  330  serve to gently conduct the rolling operation upon the forward and backward movements of the front nut  310  and the rear nut  320 . Accordingly, even though the book is located on the book holding stand  400 , the forward and backward movements of the front nut  310  and the rear nut  320  are conducted more gently manner through the guide wheels  330 . 
     On the other hand, the underside surface of the book can be supported over a relatively large area on left and right sides thereof by means of the telescoping left and right supporting members  410 , while being supported through the book holding stand  400 . However, the left and right sides of the book are supported by means of the left and right supporting members  410 , but if the height of the book is increased, the book is not supported well through the left and right supporting members  410 . So as to solve these problems, as shown in  FIGS. 6 and 7 , the auxiliary book holding stand  700  is coupled to the rear end portion of the book holding stand  400  in such a manner as to be slidingly moved forwardly and backwardly. The auxiliary book holding stand  700  is coupled to the rear end portion of the book holding stand  400  and slidingly moved in the forward and backward directions of the book holding stand  400  to support the underside surface of the book over a relatively large area together with the book holding stand  400 . At this time, the auxiliary book holding stand  700  is slidingly moved forwardly and backwardly through a guide member inserted into the book holding stand  400 . In the same manner as the book holding stand  400 , at this time, the auxiliary book holding stand  700  may have an auxiliary left and right supporting member  710  extended and contracted in a telescoping manner in the left and right directions from the inside thereof so as to support the underside surface of the book. 
     However, if the size of the book is increased, it is difficult to rigidly support the bottom end of the book only with the bottom supporting member  420 , and thus, in the same manner as the auxiliary book holding stand  700  and the auxiliary left and right supporting member  710 , as shown in  FIGS. 8 and 9 , a pair of auxiliary left side bottom supporting member  810  and auxiliary right side bottom supporting member  820  is rotatably coupled to the left and right sides of the bottom supporting member  420  on one end thereof and turned on the other end thereof in such a manner as to be extended in left and right directions of the bottom supporting member  420 . Accordingly, even though the large-sized book is located on the book holding stand  400 , the bottom end of the book can be more rigidly fixed over the relatively large area by means of the bottom supporting member  420  and the auxiliary left and right side bottom supporting members  810  and  820 . At this time, in case where the bottom end of the book is supported by means of the auxiliary left and right side bottom supporting members  810  and  820 , the open state of the book can be maintained even though the book is not pressed on the open state by means of a user&#39;s hand, thereby making it convenient to use. That is, as shown in  FIGS. 8 and 9 , the auxiliary left and right side bottom supporting members  810  and  820  further have a pair of left side fixing protrusion  811  and right side fixing protrusion  821  formed on the top surfaces of the other surfaces thereof so as to fix both side bottom ends of the open book, thereby allowing the open state of the book supported by means of the book holding stand  400  to be maintained. If the book is supported by means of the auxiliary left and right side bottom supporting members  810  and  820  in the open state, the pair of left side fixing protrusion  811  and right side fixing protrusion  821  is brought into contact with the bottom ends of both sides of the open book, thereby preventing the book being in the open state from being closed to allow the book to be maintained in the open state. 
     While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention. 
     The portable book holder according to the present invention is applicable to the industrial field where a portable book holder is manufactured, whereby the portable book holder can be easily carried and the book holding stand can be adjusted to the user&#39;s desired arbitrary angle.