Abstract:
A universal bookholder which receives a book therein in a folder type, and which is portable and usable anywhere at any time to allow a user to read a book thereon is disclosed. The universal bookholder includes a pair of cover members for forming an inner space to receive a book therein when being folded and for supporting both sides of the book when being opened, a supporting unit combined between the pair of cover members so as to be folded with the cover members, a string installed in the supporting unit to traverse papers of the book for fixing the received book, at least one guide member mounted in the pair of cover members, and a clamp movably combined to the guide member for fixing a paper of the received book.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of PCT International Patent Application No. PCT/KR2004/000064, filed Jan. 15, 2004, Korean Patent Application No. 2003-100107, filed Dec. 30, 2003, in the Korean Intellectual Property Office, and Korean Patent Application No. 2003-59081, filed Aug. 26, 2003, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a bookholder, and more particularly to a universal bookholder receiving a book in a folder type so that the book may be carried easily, thereby enabling users to read the book anywhere at any time.  
         [0004]     2. Description of the Related Art  
         [0005]     A bookholder is generally mounted on a table to facilitate reading a book. The bookholder basically includes a stand for putting a book thereon, a support assembly for adjusting the stand at a certain angle to conform to the level of vision, and a clamp for biasing papers of the book. There have been proposed various kinds of bookholders with such basic configuration.  
         [0006]     However, these bookholders are designed to be used on a table in a school, library or study room, so they are not useful while a user is moving outdoors. Thus, there is a need for a portable bookholder which allows a student who is struggling for studying even on their way to school and home, or a worker who uses public transportation for commuting to enjoy reading during his/her movement, not in a limited places such as a table. Portable bookholders which are improved for easy carrying it by reducing its weight and size are also proposed. However, they are inconvenient because a user should carry a book separate from the bookholder.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention is designed to solve the problems of the prior art, and therefore the object of the invention is to provide a universal bookholder which is capable of receiving and carrying a book therein so that a user may read the book at any place.  
         [0008]     Another object of the invention is to provide a bookholder by which users can read a book when he/she is lying down, standing or sitting down even without holding the book in his/her hands.  
         [0009]     In order to accomplish the above object, the present invention provides a bookholder, which includes a pair of cover members for forming an inner space to receive a book therein when being folded and for supporting both sides of the book when being unfolded; a supporting unit combined between the pair of cover members so as to be folded with respect to the each cover member; a string longitudinally installed inside the supporting unit to fix the spine of the book; and at least one clamp installed inside the cover member and having a lifting unit for selectively fixing a height of the clamp depending on a thickness of the book so as to fix the pages of the received book.  
         [0010]     Preferably, the supporting unit has a width selectively extendable depending on a thickness of the book.  
         [0011]     Also preferably, the bookholder further comprises an illuminating unit for emitting light toward the book received in the cover member.  
         [0012]     Preferably, a handle is provided on an outer surface of the supporting unit or the cover member.  
         [0013]     Also, a plurality of concave grooves are prepared on an outer surface of the bookholder at regular intervals and a knob selectively fixed to the grooves is provided to the bookholder so as to facilitate easy grip of the bookholder during movement or reading.  
         [0014]     According to another aspect of the invention, there is provided a bookholder comprising: a pair of cover members for forming an inner space to receive a book therein when being folded and for supporting both sides of the book when being unfolded; a supporting unit combined between the pair of cover members so as to be folded with respect to the each cover member, and having a receiving groove longitudinally formed thereon; a string longitudinally installed inside the supporting unit to fix the spine of the book; at least one clamp installed inside the cover member for fixing the pages of the received book; and a support assembly having a size corresponding to the receiving groove, and pivotally installed in the receiving groove by means of a hinge.  
         [0015]     Preferably, the supporting unit has an inner space of which one end has an opening, and the bookholder further comprises a sliding support member received in the inner space of the supporting unit to slide into or out through the opening; at least one ring formed to connect a support string to the sliding support member; and a pair of auxiliary support arms installed on both sides of the sliding support member and capable of being bent.  
         [0016]     More preferably, the supporting unit has an inner space of which one end has an opening, and the bookholder further comprises a case provided in the supporting unit and having an opening corresponding to the opening of the supporting unit; and a support assembly having a sliding support member received in the inner space of the case and sliding into or out through the opening of the supporting unit, wherein the support assembly is pivotally combined to the supporting unit.  
         [0017]     Also, the bookholder further comprises a locking means for keeping the cover members unfolded.  
         [0018]     Preferably, the locking means includes at least one push hook provided on either the supporting unit or the cover member; and a hook groove formed on either the cover member or the supporting unit so that the push hook is inserted therein.  
         [0019]     As an alternative, the locking means includes a bar installed on one of the cover members; a concave groove formed on the other one of the cover members so that the bar is inserted therein; and a switch for biasing the bar toward the concave groove.  
         [0020]     According to another aspect of the invention, there is provided a bookholder comprising: a pair of cover members for forming an inner space to receive a book therein when being folded and for supporting both sides of the book when being unfolded; a supporting unit combined between the pair of cover members so as to be folded with respect to the each cover member; a string longitudinally installed inside the supporting unit to fix the spine of the book; at least one guide member mounted inside the pair of cover members; and a clamp movably combined to the guide member for fixing the pages of the received book.  
         [0021]     Preferably, the bookholder further comprises at least one support plate combined to an inner side of the cover member in order to support a book cover; and an elastic member for elastically biasing the support plate to hold up and support the book cover.  
         [0022]     More preferably, the support plate has width and length extension units which are selectively extendable according to a size of the book respectively.  
         [0023]     Also preferably, the support plate has an inclined portion for supporting an inclined book cover and a flat portion bent from the inclined portion for supporting the book cover.  
         [0024]     Also, the bookholder may further comprise a position fixing unit selectively fixed to the supporting unit so as to adjust a length of the string depending on a size of the book.  
         [0025]     Preferably, the bookholder further comprises a stand which the bookholder is installed.  
         [0026]     More preferably, the stand includes a base; an arm extended from the base and having a plurality of joints to allow the bookholder to be located at a predetermined position; and a connector provided on an end of the arm and combined to a connector groove of the bookholder. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0027]     These and other features, aspects, and advantages of preferred embodiments of the present invention will be more fully described in the following detailed description, taken accompanying drawings. In the drawings:  
         [0028]      FIG. 1  is a perspective view showing a bookholder according to an embodiment of the present invention;  
         [0029]      FIG. 2  is a perspective view showing a bookholder according to another embodiment of the present invention;  
         [0030]      FIG. 3  is a perspective view showing a clamp moving unit of the bookholder according to another embodiment of the present invention;  
         [0031]      FIG. 4  is a sectional view showing a clamp moving unit of the bookholder according to another embodiment of the present invention;  
         [0032]      FIG. 5  is a perspective view for illustrating operation of a supporting unit according to an embodiment of the present invention;  
         [0033]      FIG. 6  is an exploded perspective view showing a support assembly according to an embodiment of the present invention;  
         [0034]      FIG. 7  shows a supporting unit according to another embodiment of the present invention;  
         [0035]      FIG. 8  is a sectional view showing the supporting unit of  FIG. 7 ;  
         [0036]      FIG. 9  is a schematic view showing a handle according to the present invention;  
         [0037]      FIG. 10  shows that the bookholder according to an embodiment of the present invention is actually used; and  
         [0038]      FIG. 11  shows a stand of the bookholder according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0039]     Hereinafter, preferred embodiments of the present invention will be described in detail referring to the accompanying drawings. Prior to the description, it should be understood that the terms used in the specification and appended claims should not be construed as limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to technical aspects of the present invention on the basis of the principle that the inventor is allowed to define terms appropriately for the best explanation. Therefore, the description proposed herein is just a preferable example for the purpose of illustrations only, not intended to limit the scope of the invention, so it should be understood that other equivalents and modifications could be made thereto without departing from the spirit and scope of the invention.  
         [0040]      FIG. 1  is a perspective view schematically showing a bookholder according to an embodiment of the present invention. Referring to  FIG. 1 , the bookholder of this embodiment includes a pair of cover members  100  and  200 , and a supporting unit  500  installed between the cover members  100  and  200 .  
         [0041]     One end of each cover member  100  or  200  is combined to the supporting unit  500 , and the cover members  100  and  200  may be folded each other about the supporting unit  500  to thereby form an inner space for receiving a book therein.  
         [0042]     Each cover member  100  or  200  has a sidewall  102  and  202  protruding a predetermined height on the edge. When the cover members  100  and  200  are folded, the sidewalls  102  and  202  form the inner space for receiving a book together with the supporting unit  500 . That is to say, the sidewall  102  or  202  has a height matched to a half width of the supporting unit  500 , so the sidewalls  102  and  202  contact each other along the center line of the supporting unit  500  forming an inner space when the cover members  100  and  200  are folded.  
         [0043]     On the inner surface of the cover member  100  or  200  where a book is received, a support plate  110  or  210  for supporting a front or rear book cover in contact is installed. Specifically, a recess  115  or  215  is formed in the inner surface of the cover member  100  or  200  so that the support plate  110  or  210  may be rotated into the recess  115  or  215 . The support plate  110  or  210  is configured to have size and thickness suitable for supporting general books.  
         [0044]     Preferably, the support plate  110  or  210  is hinged to the cover member  100  or  200  so that it may be pivoted about the supporting unit  500 . In addition, between the support plate  110  or  210  and a bottom of the recess  115  or  215  or at the hinged portion, an elastic member  112  or  212  such as a spring, a coil spring or a leaf spring may be provided to elastically and upwardly bias a book supported thereon. Alternatively, the support plate  110  or  210  may be installed on either of the cover members  100  and  200 .  
         [0045]     A clamping means  120  for fixing the received book is provided to the upper and/or lower end of the inner space of the cover members. Preferably, the clamping means  120  biases the upper and lower portion of the book in order to prevent unintentional turnover of the pages or movement of the book during reading.  
         [0046]     The clamping means  120  includes a clamp  130  for suppressing the pages of the book and a guide member  140  for moving the clamp  130  in a horizontal direction.  
         [0047]     Specifically, as shown in an enlarged view in a circle of  FIG. 1 , the clamp  130  includes a body  131  combined to the guide member  140  so as to be movable horizontally or widthwise with respect to the book, and a protrusion pressing unit  132  whose one end is pivotally combined to a front end of the body  131  to bias the pages of the book. Preferably, the protrusion pressing unit  132  is combined to the body  131  so as to be elastically pivotal by means of an elastic member  134 . Thus, when a user pushes a page of the book down with pressing the protrusion pressing unit  132  in order to read the next page, the page is inserted with pivoting the protrusion pressing unit  132 . The protrusion pressing unit  132  is then restored to its original position due to the elastic member, thereby fixing the page below it.  
         [0048]     The clamp  130  can move along the guide member  140  so that a fixed portion of the page may be selected. For this purpose, a toothed member  141  for fixing a position of the clamp  130  is provided on the guide member  140 , and an elastic protrusion  331  (see  FIG. 3 ) of the clamp  130  is joined to a selected position of the toothed member  141 . As a result, a position for fixing the page of the book may be determined by moving the clamp  130  in the horizontal direction and then positioning it at a certain position of the toothed member  141 . At this time, an adjustment surface  131  a having a rough face may be provided on the upper surface of the body  131  in order to facilitate position adjustment of the clamp  130 . Such a position determining means is not limited to this embodiment, but it should be understood that various modifications may be applied thereto with the use of well-known techniques.  
         [0049]     Preferably, according to this embodiment, the guide member  140  may be configured to be movable in the vertical direction and lengthwise with respect to the book. Specifically, a vertical guide  142  having teeth is formed on the inner side of the cover member  100  or  200 , and an elastic protrusion (not shown) corresponding to the teeth is formed on the guide member  140  so that the elastic protrusion is engaged at the selected position of the vertical guide  142 . Thus, a user may set a vertical position of the guide member  140  according to size of the book.  
         [0050]     On the inner side of the cover members  100  and  200 , protrusions  150  for placing a pen or pencil may be provided. The protrusions  150  are spaced a predetermined distance so that the pen or pencil may be fit therebetween. In addition, it is also possible to form a receiving space in a bottom portion of the cover member  100  or  200 , and then install a cover  160  (see  FIG. 5 ) so that writing tools or scratch papers may be stored therein.  
         [0051]     In addition, the cover members  100  and  200  may have an illuminating unit  170  for allowing a user to read the book in the dark. Preferably, the illuminating unit  170  is formed in one or both of the sidewalls of the cover members  100  and  200 , and received in an insertion groove  104  so as not to obstruct opening or closing the cover members  100  and  200 .  
         [0052]     Specifically, the illuminating unit  170  includes a rotating member  172  of which one end is hinged so as to be pivotal at the insertion groove  104 , and a lamp body  174  of which a center portion is rotatably hinged to the other end of the rotating member  172 . The lamp body  174  has lamps  176  at both ends, and the lamps  176  may be rotated about the lamp body  174  so as to adjust an angle of the illumination.  
         [0053]     In addition, a power source  178  for supplying power to the illuminating unit  170  is provided to the cover member  100  and/or  200 . The power source  178  is installed in the sidewall adjacent to the illuminating unit  170 , and preferably adopts a battery so as to ensure power supply while the bookholder is carried.  
         [0054]     According to this embodiment, a locking unit  180  is also provided on the bookholder in order to keep the cover members  100  and  200  unfold. Preferably, the locking unit  180  includes at least one bar  182  on the upper or lower end of one of both sidewalls  102  and  202  of the cover members  100  and  200 , and a hook groove  184  formed in the other one of the sidewalls  102  and  202  of the cover members  100  and  200  so that a leading end of the bar  182  may be inserted into the hook groove  184  when the cover members  100  and  200  are open. In order to insert the bar  182  into the hook groove  184 , a switch  186  combined to one end of the bar  182  and exposed outward is used to push the bar  182  toward the other sidewall having the hook groove  184 . At this time, it is desirable that a protrusion  182   a  is formed on the end of the bar  182  and a groove (not shown) to be engaged with the protrusion  182   a  is formed on the end of the hook groove  184  so that the inserted bar  182  is not easily taken off the hook groove  184 .  
         [0055]      FIG. 2  is a perspective view schematically showing a bookholder according to another embodiment of the present invention. The following description will be focused on different parts to the former embodiment.  
         [0056]     Referring to  FIG. 2 , the bookholder of this embodiment has a pair of cover members  300  and  400 , which are folded about a supporting unit  500  interposed therebetween to form an inner space for receiving a book.  
         [0057]     The bookholder of this embodiment does not have a sidewall, differently from the former embodiment. Instead, a clamp  330  and a string  510  installed in the inner side of the supporting unit suppress the book so that the book received between the cover members  300  and  400  and the supporting unit  500  is not loosened or deviated.  
         [0058]     On the inner sides of the cover member  300  or  400  in which the book is received, a support plate  310  or  410  for supporting the book upward in contact with a book cover is formed in a recess  315  or  415 . Preferably, the support plate  310  or  410  includes a support body  320  or  420 , and width and length extension units  326 ,  328  or  426 ,  428  respectively connected on one side of the support body  320  or  420  by a rail  325  or  425  and selectively extendable so as to adjust its width and length according to the size of the book. One end of the width extension unit  326  or  426  is hinged to the recess  315  or  415  so as to be pivotal on the supporting unit  500 .  
         [0059]     The support body  320  has a flat portion  322  and an inclined portion  324 . The flat portion  322  contacts with the book received in the cover members  300  and  400  together with the clamp  330 , thereby fixing the book more firmly rather than an inclined state. For this purpose, the flat portion  322  is pivoted on the inclined portion  324  by means of a hinge  323  interposed between the flat portion  322  and the inclined portion  324 , and supported by a support  324   a  provided at the lower end of the inclined portion  324 , as shown in an enlarged view depicted in a circle of  FIG. 2 . At this time, the flat portion  322  may be elastically pivoted using a spring, not shown. If the support plate  310  is not in use, the flat portion  322  is received in the recess  315  or  415  in parallel with the inclined portion  324 . At this time, the support plate which is biased upward by an elastic means (not shown) is locked with a hooking member  329  of the cover member  300  or  400 .  
         [0060]     According to this embodiment, the cover member  300  or  400  has the clamp  330  on its inner side in order to fix the pages of the received book. The clamp  330  is installed to give a pressing force opposite to a biasing direction of the support plate  310  or  410 .  
         [0061]      FIGS. 3 and 4  are perspective view and sectional view showing the clamp  330  of this embodiment. Referring to  FIGS. 3 and 4 , the clamp  330  has a lifting unit for selectively extending its length according to a thickness of the book. The lifting unit has a first block  332 , and a second block  334  in which the first block  332  selectively moves up and down.  
         [0062]     Specifically, the first block  332  includes an elastic hook  336  which has a hooking protrusion  336   a  at one side, and a release protrusion  336   b  adjacent to the hooking protrusion  336   a.    
         [0063]     In addition, the second block  334  has a guide slot  337  on its one sidewall, and teeth  338  formed along the inner sidewall of the second block  334 .  
         [0064]     Thus, when the first block  332  is inserted into the second block  334  downward with a spring  339  interposed therebetween, the hooking protrusion  336   a  of the elastic hook  336  descends along the teeth  338  by means of its own elastic force, and then when the first block  332  is stopped at a desired position, the hooking protrusion  336   a  of the elastic hook  336  is locked with the teeth  338  to be maintained its position.  
         [0065]     In this state, when the release protrusion  336   b  is pressed by finger in order to ascend the clamp  330 , the hooking protrusion  336   a  is released from the teeth  338 . Then, the first block  332  is ascended by the spring  339 .  
         [0066]     Here, the lifting unit, or the clamp  330 , is not limited to this embodiment, but other techniques well known in the art may be applied thereto.  
         [0067]     In addition, the elastic protrusion  331  prepared in the second block  334  as shown in  FIG. 3  is selectively combined with the toothed member  141  of the guide member  140  described in the first embodiment. In addition, a guide protrusion  333  prevents the clamp  330  from leaving the guide member  140 .  
         [0068]     According to the present embodiment, an illuminating unit  340  is detachably installed at one or both sides of the cover members  300  and  400 . This illuminating unit  340  is identical to the illuminating unit  170  of the previous embodiment, and not described in detail here. In addition, a support piece  350  for supporting the pages of the received book is provided on the cover member  300  or  400 . In case that the book received in the cover members  300  and  400  is supported only by the clamp  330 , the book is likely to pop out the bookholder when it is turned over. However, if the support piece  350  made of transparent material connects the opposite clamps  330  in the cover member  300  or  400 , the book may be kept its position well, allowing a user to read the book.  
         [0069]     According to this embodiment, the supporting unit  500  has a string  510  to keep the book received in the cover members  300  and  400  from falling off the bookholder when the bookholder is turned over. The string  510  is preferably made of elastic materials. Preferably, the string  510  may be received in a slit  520  formed in the supporting unit  500  lengthwise so as to press the center line of the open book.  
         [0070]     Preferably, one end of the string  510  is fixed to the supporting unit, and the other end is fixed to a position fixing unit  530  which is provided on the supporting unit so as to adjust a length of the string  510  according to the size of the book.  
         [0071]     Specifically, the position fixing unit  530  is configured as follows. A rectangular position fixing groove  512  is formed in one end of the supporting unit  500 . Two stages of toothed members  514  for position fixing are longitudinally formed on at least one of the inner walls of the position fixing groove  512 .  
         [0072]     A position fixing pin  532  connected to the other end of the string  510  is selectively combined with the position fixing groove  512 . This position fixing pin  532  has a body  532   a , and an auxiliary body  532   b  on the body  532   a . On both sidewalls of the body  532   a , teeth  534  engaging with the toothed members  514  are provided. In addition, combination protrusions  538  and manipulation protrusion  536  linked with the combination protrusions  538  are formed on the body  532   a  and the auxiliary body  532   b  to be movable with respect to the body  532   a  and the auxiliary body  532   b . Thus, if a user presses the manipulation protrusion  536 , the combination protrusions  538  are moved into the body  532   a . Preferably, the combination protrusions  538  are tapered to ease insertion.  
         [0073]     In order to insert the position fixing pin  532  into the position fixing groove  512 , the position fixing pin  532  is put so that the inclined surface of the combination protrusions  538  faces the position fixing groove  512 , and then pressed. Then, the combination protrusions  538  are moved into the body  532   a  and then returned due to their own elasticity and hooked between the two-stage toothed members  514  of the position fixing groove  512 . Also, the sidewall teeth  534  of the position fixing pin  532  are engaged with the two-stage toothed members  514  of the position fixing groove  512  and fixed there. Thus, the position fixing pin  532  is fixed by the combination protrusions  538  and the teeth  534 , preventing it from getting out of the position fixing groove  512 .  
         [0074]     To the contrary, in order to release the position fixing pin  532  from the position fixing groove  512 , a user pushes the manipulation protrusion  536  of the auxiliary body  532   b . Then, the combination protrusions  538  moves into the body  532   a , and the user may take out the position fixing pin  532 .  
         [0075]      FIG. 5  shows the supporting unit according to the former embodiment of the present invention. Here, the supporting unit of  FIG. 5  may be applied to the later embodiment, not limitedly.  
         [0076]     Referring to  FIG. 5 , the supporting unit  500  is provided between the cover members  100  and  200 .  
         [0077]     The supporting unit  500  includes a support assembly  600  which is adjusted at a predetermined angle so that the bookholder of the embodiment may be put on a table. The support assembly  600  is pivotal by a hinge  632  provided in a receiving groove formed along a longitudinal direction of the supporting unit. In addition, the supporting unit  500  further includes a fixing unit (not shown) for selectively fixing the support assembly  600  when the support assembly  600  is received in the receiving groove. The fixing unit may adopt various structures for attachment and detachment of the support assembly  600 .  
         [0078]     In addition, an inclination stand  615  for supporting the bookholder of this embodiment at a low angle may be pivotably mounted on the supporting unit  500 . In addition, a handle  620  is attached on the surface of the support assembly  600  so that a user may insert his/her own hand or finger(s) thereto. The handle  620  may also be attached directly to the supporting unit  500  or outer sides of the cover members  300  and  400 . A user may hold the handle  620  for carrying the bookholder as existing handheld bags, and particularly, the handle is useful in case that the bookholder is used not on the table but by holding with hands. That is, a user may insert his or her hand between the handle  620  and the supporting unit  500  or the cover members  300  and  400  to thereby support the bookholder, and adjust readable distance by using his/her arm. At this time, since the book is fixed by the clamp  330  and the string  510 , additional support is not necessary. In doing so, the handle  620  is preferably made of various elastic materials such as an elastic band.  
         [0079]     According to one embodiment of the present invention, the bookholder of this embodiment includes a locking unit in order to keep the cover members  100  and  200  open during reading. Preferably, the locking unit includes at least one push hook  560  provided to either the supporting unit  500  or the cover members  100  and  200 , and a hook groove  570  formed in either the cover members  100  and  200  or the supporting unit  500  so that the push hook  560  is inserted therein. Thus, a user firstly unfolds the cover members  100  and  200 , and then pushes the push hook  560  to be inserted into the hook groove  570 , thereby keeping the cover members  100  and  200  unfolded.  
         [0080]     In addition, the bookholder of the present invention may be useful for reading outdoors when the support assembly  600  of the supporting unit  500  is used. Referring to  FIG. 6  showing configuration of the support assembly  600 , the support assembly  600  includes a case  630 , and a cover  640  for covering the case  630 .  
         [0081]     The case  630  has a hinge  632  at its one end so that it may be pivotally combined to the supporting unit  500  as described above. Preferably, an angle adjustment groove  634  is formed in the hinge  632  for adjustment of a pivot angle of the support assembly  600 . The angle adjustment groove  634  is selectively combined with a protrusion (not shown) formed on the supporting unit  500  so as to set a pivot angle of the support assembly  600 .  
         [0082]     According to this embodiment, the other end of the case  630  has an opening so that a sliding support member  700  may be moved in and out through the opening. The sliding support member  700  is installed so that it may be put into or taken out of the inner space formed by the case  630  and the cover  640 . The sliding support member  700  may have a suitable size in accordance with the inner space.  
         [0083]     Preferably, the sliding support member  700  is hollow to form a receiving space therein and has a plurality of rings  732  mounted on its inner bottom. The rings  732  are used for connecting a support string  730 , described later. For example, a hook, not shown, tied at one end of the support string  730  may be hooked around the ring  732 .  
         [0084]     The case  630  also has a toothed hooking member  636  on its inner side in order to set a position of the sliding support member  700  when the sliding support member  700  is taken out. An elastic hook  710  of the sliding support member  700  is selectively hooked to the toothed hooking member  636  so as to fix a position of the sliding support member  700 .  
         [0085]     According to the present invention, in case the sliding support member  700  is taken out when using the bookholder, a pair of auxiliary support arms  740  may be further provided for supporting the bookholder more stably. The auxiliary support arm  740  consists of a plurality of support pieces  744  connected each other by joints  742  to be bent. In addition, one end of the auxiliary support arm  740  is combined with the sliding support member by means of a ball-type hinge so that the auxiliary support arm  740  is pivotable and rotatable in directions shown by arrows in the figure. The auxiliary support arm  740  consisting of the support pieces  744  may be bent according to the curvature of human body as described later, thereby supporting the bookholder more stably. Many well-known techniques capable of realizing such a function may be applied instead of the auxiliary support arm  740 .  
         [0086]     Preferably, at a side of the sliding support member  700 , a recess portion is preferably formed so that the auxiliary support arm  740  may be positioned therein. Thus, with the auxiliary support arm  740  folded at both sides, the sliding support member  700  may be inserted into the case  630 . In addition, an elongated hole  638  is preferably formed in the sidewall of the case  630 . The elongated hole  638  allows the auxiliary support arm  740  to be spread out with the sliding support member  700  inserted into the case  630 . For example, if the bookholder is used on an uneven place such as a bed, the support assembly  600  is installed to be inclined and then the auxiliary support arms  740  are taken out and suitably pivoted or rotated so that it may be surface-contacted on the uneven place. This allows a user to read a book stably in a lying or sitting posture.  
         [0087]     According to this embodiment, a taking-out unit for easily taking out the sliding support member  700  from the case  630  is provided at the end of the sliding support member  700 .  
         [0088]     Preferably, the taking-out unit has a grip  750  which is configured for easy grip of a user. More preferably, the grip  750  is made of rubber, or indentation may be formed on the grip for better grip.  
         [0089]      FIGS. 7 and 8  show a supporting unit according to another embodiment of the present invention. The supporting unit  800  of this embodiment is suitable for reading a book having a thickness larger than the width of the supporting unit in which the cover members are incompletely folded. Referring to  FIGS. 7 and 8 , the supporting unit  800  includes movable plates  810  and  820  which are folded with the cover members  100  and  200 , and a fixed plate  830  whose both ends are inserted into slide grooves  810   a  and  820   a  of the movable plates  810  and  820 . Thus, a width of the whole supporting unit  800  may be extended or shortened by moving the movable plates  810  and  820  in the opposite directions according to the thickness of the book.  
         [0090]     In addition, the supporting unit  800  has a hooking unit for keeping the extended or shortened width of the supporting unit. That is to say, hooks  812  and  822  are mounted on the movable plates  810  and  820 , and a plurality of hooking grooves  832  are formed on the surface of the fixed plate  830  at regular intervals along the width of the received book. As a result, by fitting the hooks  812  and  822  into the hooking groove  832 , the supporting unit  800  may keep its width fixed.  
         [0091]     In addition,  FIG. 9  shows a handle according to another embodiment of the present invention. Referring to  FIG. 9 , a plurality of concave grooves  950  are formed on the outer surface of the cover members at regular intervals. Preferably, a distance (L 2 ) between the concave grooves is identical to the distance (L 1 ) between legs of a knob, which acts as a handle. Thus, a user may hold the bookholder more easily by selectively combining the detachable knob  960  into a concave groove(s)  950  at a desired position.  
         [0092]     Now, operation of the bookholder configured as described above according to the present invention is described in detail.  
         [0093]     A user may carry a book in the bookholder according to the present invention, not putting the book into a separate folder or bag. That is to say, as shown in  FIG. 1 , the book is put into the inner space of the cover members  100  and  200  and then the cover members  100  and  200  are folded, the book may be received in the cover members  100  and  200  because the sidewalls  102  and  202  generates a sufficient inner space. In addition, in case that there is no sidewall as shown in  FIG. 2 , the book may be fixed in the cover members by using the clamp  330  and the string  510  mounted in the cover members  300  and  400  and the supporting unit  500 .  
         [0094]     The bookholder of the present invention may also be used on a fixed place such as a table. For example, the cover members  100  and  200  are unfolded straightly and then the push hook  560  prepared in the cover member is pushed into the hook groove  570  formed in the supporting unit  500 . Then, the cover members  100  and  200  are not pivoted but fixed to the supporting unit  500 . As an alternative, as shown in  FIG. 1 , the cover members  100  and  200  and the supporting unit  500  may be stably fixed to form the same surface with the use of the locking unit  180  having the bar  182  and the concave groove  184 .  
         [0095]     In this state, the support assembly  600  is pivoted backward with respect to the hinge to support the bookholder on the ground as shown in  FIG. 5 . Then, a user may read a book with the use of the bookholder of the present invention at a fixed place such as a table.  
         [0096]     Meanwhile, in order to put a book on the bookholder, a user firstly sets a position of the bookholder, opens the book by its substantially half page, and then fits the position fixing pin  532  at a suitable position with putting the string  510  in the supporting unit across the spine of the book. Then, book covers are fixed in contact with the inner surfaces of the cover members  100  and  200 . If the support plate is employed, the book is arranged so that the front cover of the book contacts with the support plate  110  and a rear cover contacts with the support plate  210 . And then, the guide member  140  is vertically adjusted to conform to the size of book, and then a position of the clamp  130  is also set.  
         [0097]     Subsequently, if a user pushes a page below the clamp  130  with turning over the page or presses the clamp  130 , the protrusion pressing unit  132  is pivoted to pass the page as mentioned above. The protrusion pressing unit  132  then restores its origin state at once by means of the elastic member  134  so that the page is supported not to be turned. At this time, the support plate  110  in contact with the front cover of the book biases the book cover upward by means of the elastic member  112 , so the page may be more stably supported between the clamp  130  and the support plate  110 . The same principle may be applied to the rear cover of the book. If the book is thick, as shown in  FIGS. 3 and 4 , a thickness of the inner space of the cover members may be selectively adjusted with the use of the extendable clamp  330 . In addition, a thicker book may be received in the bookholder by extending a width of the supporting unit  500  as shown in  FIGS. 7 and 8 .  
         [0098]     According to the present invention, in the above state, since a user inserts one hand into the handle  620  on the outside of the supporting unit  500  or the cover members  100  and  200  to thereby uniformly transfer the center of weight through the arm, he/she can read the book in anyplace. Particularly, in a vehicle such as a subway or a bus a user can hold a handle of the vehicle by one hand with the other hand inserted into the handle  620  to support the bookholder as he/she likes, which enables a user to comfortably read the book when standing in a vehicle.  
         [0099]     Also, when a user folds the cover members  100  and  200  of the bookholder after reading, the book is closed and received in the bookholder in a current state. Thus, if the bookholder is open later, the page of the book is open as it was. Thus, the user need not struggle to find the page which was being read before.  
         [0100]     Meanwhile, as shown in  FIG. 10 , if a user desires to use the bookholder without the support of hands, the user pulls the handle  750  to draw out the sliding support member  700 . While the sliding support member  700  is drawn out, the elastic hook  710  comes in contact with the toothed hooking member  636  to determine its position. Thus, the sliding support member  700  may be drawn out and fixed as much as a suitable length as required.  
         [0101]     In addition, the bookholder of the present invention may be additionally supported with the use of the support string  730  by hanging the support string  730  on the neck or the shoulder of the user. That is to say, the support string  730  may be supported around the neck or the shoulder by connecting it to at least one ring  732  mounted to the sliding support member  700 . In this case, a hooking unit (not shown) having easy detachment function is prepared to the support string  730 , thereby facilitating easy connection between the support string  730  and the ring  732 . In addition, for more stable support, the support string  730  is preferably connected to a ring  732  which is positioned at a substantial center between the upper end of the bookholder and the end of the drawn sliding support member  700 .  
         [0102]     According to the present invention, in order to support the bookholder better, the auxiliary support arms  740  may be used. That is to say, if the auxiliary support arms  740  are spread and then put on the body of the user with suitable bending of the joints  742 , the bookholder may be supported more stably without lateral shaking.  
         [0103]      FIG. 11  shows a stand for fixing the bookholder of the present invention. Referring to  FIG. 11 , the bookholder may be selectively combined to a stand  900  of a predetermined structure.  
         [0104]     The stand  900  includes a base  910 , an arm  920  extended from the base  910  and having plural joints for free movement, and a connector  930  prepared at the end of the arm  920  and combined with the bookholder.  
         [0105]     The base  910  has sufficient weight and size so that the bookholder combined to the stand does not fall down, and a support clamp, not shown, may also be provided to the base. The arm  920  has at least two joints so that a user may read a book with the use of the bookholder in any posture. In addition, the connector  930  is configured to ensure power supply to the bookholder. For example, the power supply may be directly supplied from an external source to the illustrating unit. In addition, this process also may charge a power source  178  which is installed in the sidewall  102 .  
         [0106]     The present invention has been described in detail. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.  
       INDUSTRIAL APPLICABILITY  
       [0107]     The universal bookholder of the present invention has effects as follows.  
         [0108]     First, since the bookholder may be carried together with a book, the volume of the bookholder and the book is decreased than when they are carried separately. In addition, a user may carry the book and the bookholder more easily.  
         [0109]     Second, the book received in the cover members may be kept so that it may be open as it was. In addition, since the bookholder may store various pens and scratch papers, the bookholder is useful outdoors.  
         [0110]     Third, the bookholder may facilitate reading of a user who is standing in a vehicle such as a subway or a bus. Because a user who is standing in a vehicle wants to read a book, he can hold a handle of the vehicle safely by one hand by virtue of the other hand which is inserted into the handle on the outer side of the bookholder. At this time, the current page of the book is fixed by the clamp and the string, which prevents the book from leaving its position. As a result, a user does not need to struggle to hold both pages by one hand but simply insert his/her hand into the handle, and then may read easily and safely even standing in a vehicle.  
         [0111]     Fourth, the bookholder may conveniently keep a book of a certain weight within a readable distance with its pages fixed without being supported by user&#39;s hands.  
         [0112]     Fifth, the bookholder is useful while a user is moving, and the bookholder may also be put on a table. In addition, if being combined with a stand, the bookholder may be positioned within a readable distance by moving joints of the stand, so a user may read a book on the bookholder in various postures and at various angles. The bookholder even makes it possible that a user who is lying reads a book.  
         [0113]     Sixth, the bookholder allows a user to read a book with the use of the illustrating unit mounted thereto without any separate light source in a dark place.  
         [0114]     Seventh, since the cover members cover and protect the book, a user can hide the book covers that he or she does not want to show to others. Also, the book inside the bookholder can be prevented from the physical impact or outer environment. In addition, the cover members give various visual effects according to user&#39;s taste.  
         [0115]     Eighth, the bookholder can be a base on which various elements that facilitate reading may be collected.