Abstract:
A juice extracting apparatus, which can improve juice extracting efficiency without increasing a number of revolutions of a driving means, is disclosed. A juice extracting apparatus, which can easily clean components including an extracting net unit, while minimizing sludge stuck in or sticking on a component, is also disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority of Korean Patent Application No. 10-2011-0019958, filed on Mar. 7, 2011 and priority of Korean Patent Application No. 10-2011-0071359, filed on Jul. 19, 2011, in the KIPO (Korean Intellectual Property Office), the disclosure of which is incorporated herein entirely by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an apparatus for extracting juice type food by squeezing fruits, vegetables or beans. 
         [0004]    2. Description of the Related Art 
         [0005]    A juice extracting apparatus is an apparatus for extracting juice by squeezing agricultural and marine products such as fruits, vegetables or beans. 
         [0006]    The configuration and functions of a conventional juice extracting apparatus are as follows. 
         [0007]      FIG. 1  is a schematic drawing showing a conventional horizontal type juice extracting apparatus. 
         [0008]    As shown in  FIG. 1 , in the horizontal type juice extracting apparatus, when a material such as a fruit or a vegetable (to be referred to as a “raw material” hereinafter) is injected into an upper inlet  10 , the injected raw material is sliced while a screw  11  rotates as a motor  16  is driven. 
         [0009]    Thereafter, the sliced raw material is conveyed toward a squeezing nozzle  13  to then be squeezed between the screw  11  and an extracting net unit  12 , and juice extracted from the raw material is discharged to the outside through a juice outlet  15 . In addition, sludge of the discharged raw material is discharged to the outside through the squeezing nozzle  13  and a nozzle cap  14 . 
         [0010]    In addition, when a highly sticky raw material is injected, it may stick on the extracting net unit  12 , so that the amount of juice extracted is markedly reduced compared to the amount of the raw material. 
         [0011]      FIG. 2  is schematic view showing another example of a conventional juice extracting apparatus, illustrating a vertical type juice extracting apparatus. 
         [0012]    As shown in  FIG. 2 , in the vertical type juice extracting apparatus, a raw material such as a fruit or a vegetable is injected into an upper inlet  20 , and a driving means  27  is driven to rotate a pulverizing gear  23  coupled to the driving means  27 , a convey screw  22  and a shredder plate  21 . Accordingly, the injected raw material is primarily sliced in the shredder plate  21  and then conveyed toward the pulverizing gear  23  through the convey screw  22 . 
         [0013]    The juice extracted from the sliced raw material in the course of conveying is discharged to a juice guide orifice  26  via the extracting net unit  24 , and sludge of the raw material existing between the pulverizing gear  23  and the extracting net unit  24 , from which juice has been extracted, is discharged to the outside through the sludge guide orifice  25 . 
         [0014]    The horizontal type juice extracting apparatus and the vertical type juice extracting apparatus are configured such that a screw or a pulverizing gear is solely rotated for extracting juice. Thus, in order to improve juice extracting efficiency, it is necessary to increase a number of revolutions of a motor. In this case, load may be applied to a driving means, thereby shortening a cycle life, increasing the amount of heat generated and increasing power consumption. 
         [0015]    In addition, if a rotational speed of the driving means increases to exceed a predetermined range, nutrients of juice may be destructed, so that there is a limit in increasing the number of revolutions. That is to say, from the nutritional viewpoint, the juice extracting apparatus is preferably driven at a low speed, rather than at a high speed. 
         [0016]    In the horizontal or vertical type juice extracting apparatus having an extracting net unit fixedly installed, when protrusions or grooves are soiled with sludge, it is quite difficult to perfectly wash the juice extracting apparatus. 
       SUMMARY OF THE INVENTION 
       [0017]    Aspects of the present invention provide a juice extracting apparatus, which can improve juice extracting efficiency without increasing a number of revolutions of a driving means. 
         [0018]    Aspects of the present invention also provide a juice extracting apparatus, which can easily clean components including an extracting net unit, while minimizing sludge stuck in or sticking on a component. 
         [0019]    In accordance with one aspect of the present invention, there is provided a juice extracting apparatus including an extracting case having a juice outlet and a sludge outlet communicating an internal space thereof with an outside, an extracting screw unit positioned in the internal space of the extracting case, having a screw blade formed on its outer peripheral surface, a screw shaft connected to a drive shaft of a driving means at a lower end and a sun gear mounted at the lower end of the screw shaft, a rotary extracting net unit in which the extracting screw unit is positioned, the rotary extracting net unit comprising a mesh net corresponding to the screw blade to filter sludge while allowing juice to pass therethrough, and a ring gear provided at its lower portion, and a discharge guide unit positioned at the lower portion of the rotary extracting net unit, having planet gears engaged between the sun gear and the ring gear and transmitting a rotational force of the extracting screw unit to the rotary extracting net unit, and guiding the sludge resulting from the extracting, wherein the juice squeezed from a raw material injected while the extracting screw unit and the rotary extracting net unit rotate in opposite directions from each other is discharged through an outlet of the extracting case and the sludge is discharged to the outside through a sludge outlet. 
         [0020]    The screw blade may have screw threads having a pitch interval gradually narrowing toward its bottom end from its top end. 
         [0021]    The rotary extracting net may have at least one or more guide protrusions downwardly extending on its inner surface to convey the injected raw material downwardly in a geared manner with the screw threads of the screw blade. 
         [0022]    The extracting case may further include a brush for removing sludge in contact with and sticking on the outer peripheral surface of the rotary extracting net fixed on its inner surface and rotating. 
         [0023]    The rotary extracting net unit may further include a brush mounted on its outer peripheral surface and making a contact with the inner surface of the extracting case. 
         [0024]    The rotary extracting net unit may further include at least one rotary protrusion formed on the outer peripheral surface of its bottom end, the at least one rotary protrusion forcibly conveying the juice existing on the bottom of the rotary extracting net unit to the juice outlet. 
         [0025]    The rotary extracting net unit may further include a cleaner mounted on its outer peripheral surface and capable of rotating together with the rotary extracting net unit. Preferably, the cleaner has a rubber fixed on its inner surface and inwardly extending to correspond to the mesh net of the rotary extracting net unit. 
         [0026]    The cleaner may have interior grooves radially formed on its inner peripheral surface and the rotary extracting net unit may have exterior protrusions radially formed on its outer peripheral surface, so that the exterior protrusions of the rotary extracting net unit are accommodated in the interior grooves of the cleaner, thereby guiding rotation of the cleaner. 
         [0027]    The cleaner may further include a stopper protrusion fixed on its outer peripheral surface and the extracting case may further include a hooking portion formed on its outer peripheral surface and outwardly protruding, so that the cleaner does not rotate and only the rotary extracting net unit rotates when the stopper protrusion and the hooking portion make a contact with each other, and the rubber of the cleaner removes the sludge sticking on the mesh net of the rotary extracting net unit is removed. 
         [0028]    The juice extracting apparatus may further include a cleaner fixed on the extracting case and made of an elastic material, wherein the cleaner make a contact with the rotating extracting net unit and forcibly removes the sludge sticking on the mesh net of the rotary extracting net unit. 
         [0029]    The cleaner may include a fitting portion fitted into the hooking portion formed in the extracting case and an extending portion extending from the fitting portion to the rotary extracting net unit and making a contact with the net unit of the rotating rotary extracting net unit. 
         [0030]    The discharge guide unit may further include a guide rubber fixedly installed at a bottom end of the outlet and capable of elastically opening or closing the outlet at its one side. 
         [0031]    The juice extracting apparatus may further include an injection cover coupled to the extracting case and including an inlet for injecting the raw material, an injection pipe integrally formed with the inlet so that the injected raw material is vertically conveyed, and a plurality of engagement protrusions radially formed at a bottom portion of the injection cover to be engaged with the extracting case. 
         [0032]    The juice extracting apparatus may further include a sensor sensing a current varying according to the load applied to the drive shaft of the driving means, and a controller connecting the sensor and the driving means, wherein when overload is applied to the drive shaft, the controller controls the driving means capable of rotating forward and backward to rotate backward for a predetermined time to then rotate forward. 
         [0033]    As described above, in the juice extracting apparatus according to the present invention, an extracting screw unit rotates in a first direction and a rotary extracting net unit rotates in a second direction opposite to the first direction in which the extracting screw unit rotates, thereby improving juice extracting efficiency even with a small driving force (a rotational force). 
         [0034]    In addition, since the extracting screw unit and the rotary extracting net unit rotate in opposite directions, sludge existing between the extracting screw unit and the rotary extracting net unit can be minimized and effectively cleaning the outer peripheral surface of the rotary extracting net unit. 
         [0035]    Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0036]    The above and other features and advantages will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments with reference to the attached drawings, in which: 
           [0037]      FIG. 1  is a schematic diagram of a general horizontal type juice extracting apparatus; 
           [0038]      FIG. 2  is schematic diagram of another example of a general juice extracting apparatus, illustrating a vertical type juice extracting apparatus; 
           [0039]      FIG. 3  is a perspective view of a juice extracting apparatus according to a first embodiment of the present invention; 
           [0040]      FIG. 4  is an exploded perspective view of the juice extracting apparatus shown in  FIG. 3 ; 
           [0041]      FIG. 5  illustrates a state in which an injection cover is removed from the juice extracting apparatus shown in  FIG. 3 ; 
           [0042]      FIG. 6  is a partially sectional view of  FIG. 5 ; 
           [0043]      FIG. 7  is a bottom view of  FIG. 6 ; 
           [0044]      FIG. 8  illustrates a state in which a discharge guide unit and an extracting case shown in  FIG. 4  are assembled to each other; 
           [0045]      FIG. 9  illustrates an operating state of the juice extracting apparatus shown in  FIG. 3 ; 
           [0046]      FIG. 10  is an exploded perspective view of a juice extracting apparatus according to a second embodiment of the present invention 
           [0047]      FIG. 11  illustrates a cleaner shown in  FIG. 10   
           [0048]      FIG. 12  is a bottom perspective view of a discharge guide shown in  FIG. 10 ; 
           [0049]      FIG. 13  illustrates an interior side of an extracting case shown in  FIG. 10 ; 
           [0050]      FIG. 14  illustrates a state in which the cleaner shown in  FIG. 10  is installed inside the extracting case together with a rotary extracting net unit; 
           [0051]      FIG. 15  is a cross-sectional view of the juice extracting apparatus shown in  FIG. 10 , in which a driving means shown in  FIG. 10  is not illustrated; 
           [0052]      FIG. 16  illustrates an interior side of an extracting case of an according to a third embodiment of the present invention; 
           [0053]      FIG. 17  is a perspective view of a cleaner shown in  FIG. 16 ; and 
           [0054]      FIG. 18  is a cross-sectional view of a juice extracting apparatus with cleaners shown in  FIGS. 16 and 17 , in which a driving means shown in  FIG. 16  is not illustrated. 
       
    
    
       [0055]    In the following description, the same or similar elements are labeled with the same or similar reference numbers. 
       DETAILED DESCRIPTION 
       [0056]    The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
         [0057]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
         [0058]    Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
         [0059]    Preferred embodiments will now be described more fully hereinafter with reference to the accompanying drawings. However, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. 
         [0060]    Hereinafter a juice extracting apparatus according to a first embodiment of the present invention will be described. 
         [0061]    As shown in  FIGS. 3 to 5 , the juice extracting apparatus according to the first embodiment of the present invention includes an injection cover  100 , an extracting screw unit  110 , a rotary extracting net unit  120 , a discharge guide unit  130  and an extracting case  140 . 
         [0062]    First, the injection cover  100  includes a hopper-shaped inlet  101  formed at its top portion to inject a material for extracting juice, such as fruits or vegetables (hereinafter, referred to as “raw material”); an injection pipe  102  integrally formed with the inlet  101  at a lower portion of the inlet  101  so that the injected raw material is vertically conveyed, and a plurality of engagement protrusions  103  radially formed at a bottom portion of the injection cover  100  to be engaged with the extracting case  140 . 
         [0063]    The extracting screw unit  110  includes a screw shaft  113  (shown in  FIG. 6 ) having an insertion protrusion  114  formed at its top end and an insertion groove  115  (shown in  FIGS. 6 and 7 ) formed at its bottom end; a screw blade  111  having a pitch and screw threads gradually decreasing toward its bottom end from its top end with respect to the screw shaft  113 ; and a sun gear  112  fixed at a bottom of the screw shaft  113 . 
         [0064]    An insertion groove  116  (shown in  FIGS. 6 and 7 ) is formed at the center of the bottom of the screw  110  to be placed on the extracting case  140 . The screw shaft  113  is connected to a drive shaft (not shown) of a driving means (not shown) positioned outside the extracting case  140 . 
         [0065]    The rotary extracting net unit  120  is a cylindrical structure and the extracting screw unit  110  is disposed inside the rotary extracting net unit  120 . The rotary extracting net unit  120  includes one or more guide protrusions  121  downwardly extending on the inner surface of the rotary extracting net unit  120  to convey the injected raw material downwardly in a geared manner with the screw blade  111 ; a mesh net  122  formed at top and bottom portions of its outer peripheral surface to filter sludge of the raw material while allowing juice to pass therethrough; and a ring gear  123  fixed at its bottom end. 
         [0066]    The discharge guide unit  130  includes a sludge outlet  132  positioned at a lower portion of the rotary extracting net unit  120  and allowing the sludge of the compressed and juice-extracted raw material to be discharged; an interior protrusion  133  and an exterior protrusion  134  maintaining pressures at bottom ends of the extracting screw unit  110  and the rotary extracting net unit  120 ; planet gears  131  engaged between the sun gear  112  of the extracting screw unit  110  and the ring gear  123  of the rotary extracting net unit  120  and transmitting a rotational force of the extracting screw unit  110  to the rotary extracting net unit  120 ; and a fixing shaft  135  (shown in  FIG. 7 ) for fixing each of the planet gears  131 . 
         [0067]    As shown in  FIG. 8 , the extracting case  140  has top engagement units  144  coupled to the engagement protrusions  103  of the injection cover  100 . A juice outlet  141  and a sludge outlet  142  communicating an internal space of the extracting case  140  with an outside are formed at opposite sides of the extracting case  140 . 
         [0068]    In particular, as shown in  FIGS. 6 and 8 , an interior bottom portion of the extracting case  140  is flatly configured to accommodate the extracting screw unit  110 , the rotary extracting net unit  120  and the discharge guide unit  130 . In addition, a cylindrical bushing  145 , to which the extracting screw unit  110 , specifically a sun gear  112  and a drive shaft of a driving means (not shown) are engaged, is formed at the center of the extracting case  140 . 
         [0069]    Meanwhile, the extracting case  140  may further include a brush  143  fixed at one side of its inner surface and extending upwardly. 
         [0070]    Hereinafter, the operation of the juice extracting apparatus according to the first embodiment of the present invention will be described with reference to the following drawings. 
         [0071]    As shown in  FIG. 9 , if a raw material such as a fruit, vegetable or beans is injected into the inlet  101  of the injection cover  100 , the extracting screw unit  110  engaged with the drive shaft (not shown) of the driving means (not shown but installed below the extracting case  140 ) rotates, thereby slicing the raw material by the screw blade  111 . 
         [0072]    Meanwhile, as shown in  FIG. 7 , the sun gear  112  of the extracting screw unit  110 , the plurality of planet gears  131  of the discharge guide unit  130 , and the ring gear  123  of the rotary extracting net unit  120  are engaged with each other, thereby allowing the rotary extracting net unit  120  to rotate in an opposite direction to a direction in which the extracting screw unit  110  rotates according to the rotation of the extracting screw unit  110 . 
         [0073]    Here, a distance between the outer peripheral surface of the extracting screw unit  110  and the inner peripheral surface of the rotary extracting net unit  120  gradually decreases toward a lower end of the extracting screw unit  110 , and the conveyed raw material is compressed therebetween. As described above, the raw material is downwardly conveyed by the guide protrusions  121  of the rotary extracting net unit  120  rotating in the opposite direction to the rotating direction of the extracting screw unit  110 , thereby compressing and pulverizing the raw material. 
         [0074]    The juice extracted from the raw material with a high pressure moves to a space between the rotary extracting net unit  120  and the extracting case  140  through the mesh net  122  of the rotary extracting net unit  120 , to then be discharged to the outside through the juice outlet  141  of the extracting case  140 , as indicated by an arrow in  FIG. 9 . 
         [0075]    Meanwhile, the downwardly conveyed sludge is subjected to the maximum pressure at the discharge guide unit  130  to have the minimized volume thereat to then be discharged to the outside through the outlet  132  of the discharge guide unit  130  and the sludge outlet  142  of the extracting case  140 . 
         [0076]    As described above, the raw material is compressed and the juice is extracted from the compressed raw material while the extracting screw unit  110  and the rotary extracting net unit  120  rotate in opposite directions. Accordingly, the amount of sludge existing between the extracting screw unit  110  and the rotary extracting net unit  120  rotating in opposite directions can be minimized. 
         [0077]    Here, the sludge sticking on the outer surface of the rotary extracting net unit  120  is separated and removed from the outer surface of the rotary extracting net unit  120  by the brush  143  formed at one side of the inner surface of the extracting case  140 . Therefore, the sludge sticking on the mesh net  122  can be cleanly removed. 
         [0078]    Hereinafter, a juice extracting apparatus according to a second embodiment of the present invention will be described with reference to the drawings. For brevity, in the following embodiment, components having substantially the same function as the first embodiment are identified by the same reference numerals, and detailed descriptions thereof will be omitted. 
         [0079]    As shown in  FIG. 10 , like the juice extracting apparatus according to the first embodiment of the present invention, the juice extracting apparatus according to the second embodiment of the present invention includes an injection cover  200 , an extracting screw unit  210 , a rotary extracting net unit  220 , a discharge guide unit  230  and an extracting case  240 . However, unlike the juice extracting apparatus according to the first embodiment of the present invention, the juice extracting apparatus according to the second embodiment of the present invention further includes a cleaner  260  mounted on the outer peripheral surface of the rotary extracting net unit  220 . 
         [0080]    Meanwhile,  FIG. 10  illustrates a housing  250  in which a driving means (not shown) for rotating the extracting screw unit  210  is received and to which the above structural members are mounted. It is understood that a driving means housing having the same configuration and functions as those of the driving means housing  250  is also provided in the juice extracting apparatus according to the first embodiment of the present invention. 
         [0081]    The overall configurations of the injection cover  200 , the extracting screw unit  210  and the rotary extracting net unit  220  are substantially the same as the injection cover  100 , the extracting screw unit  110  and the rotary extracting net unit  120  of the juice extracting apparatus according to the first embodiment of the present invention. Here, the rotary extracting net unit  220  may further includes a brush  204  mounted on its outer peripheral surface. 
         [0082]    Meanwhile, the cleaner  260 , which is mounted on the outer peripheral surface of the rotary extracting net unit  220  in an interference fit manner, has a C-letter shape with a portion cut and may rotate together with the rotary extracting net unit  220 . 
         [0083]    At least one rotary protrusion  226  may be formed on the outer peripheral surface of a bottom end of the rotary extracting net unit  220 . The at least one rotary protrusion  226  forcibly conveys the juice existing on the bottom of the rotary extracting net unit  220  to the juice outlet  241  while rotating with the rotary extracting net unit  220 . 
         [0084]    As shown in  FIG. 11 , the cleaner  260  has interior grooves  265  coupled to exterior protrusions  225  of the rotary extracting net unit  220 . In addition, the cleaner  260  includes a stopper protrusion  266  corresponding to a hooking portion  246  (shown in  FIG. 13 ) of the extracting case  240  for stopping rotation of the rotary extracting net unit  220  when the rotary extracting net unit  220  rotates, and a cleaner rubber  262  elastically installed within the rotary extracting net unit  220  to wipe up a mesh net  222  positioned at a lower portion of the rotary extracting net unit  220 . 
         [0085]    Here, the stopper protrusion  266  is assembled with the rotary extracting net unit  220  to then be placed on a bottom surface inside the extracting case  240 , irrespective of its position, and selectively makes a contact with the hooking portion  246  of the extracting case  240 , thereby restricting rotation of the rotary extracting net unit  200 . 
         [0086]    As shown in  FIG. 12 , the discharge guide unit  230  includes an outlet  232  through which sludge of a compressed and juice-extracted raw material is discharged; an interior protrusion  233  and an exterior protrusion  234  maintaining pressures at bottom ends of the extracting screw unit  210  and the rotary extracting net unit  220 ; planet gears  231  engaged between a sun gear  212  of the extracting screw unit  210  and a ring gear  223  of the rotary extracting net unit  220  and transmitting a rotational force of the extracting screw unit  210  to the rotary extracting net unit  220 ; and a fixing shaft  235  for fixing each of the planet gears  231 . 
         [0087]    In the juice extracting apparatus according to the embodiment of the present invention, the discharge guide unit  230  further includes a guide rubber  236  fixed at a bottom end of the outlet  232 . The guide rubber  236  elastically opens or closes the outlet  232  at its one side  256 - 1 . 
         [0088]    Meanwhile, the planet gears  231  may be integrally fixed in the discharge guide unit  230  or may be detachably installed in the discharge guide unit  230 . 
         [0089]    The extracting case  240  has top engagement units  243  coupled to the engagement protrusions  203  of the injection cover  200 . A juice outlet  241  and a sludge outlet  242  communicating an internal space of the extracting case  240  with an outside are formed at opposite sides of the extracting case  240 . 
         [0090]    In particular, as shown in  FIG. 13 , an interior bottom portion of the extracting case  240  is flatly configured to accommodate the extracting screw unit  210 , the rotary extracting net unit  220  and the discharge guide unit  230 . In addition, a circular protrusion  245 , to which the extracting screw unit  210  and a drive shaft  241  of a driving means are engaged, is formed at the center of the extracting case  240 . 
         [0091]    In addition, the extracting case  240  has the hooking portion  246  fixed at a front end of the juice outlet  241 , the hooking portion  246  having a U-latter shape, corresponding to the stopper protrusion  266  formed on the outer peripheral surface of the cleaner  260 . The hooking portion  246  may have various shapes as long as it matches with the stopper protrusion  266  of the cleaner  260 . 
         [0092]    A driving means (not shown) is installed within the driving-means housing  250 , and the drive shaft  251  of the driving means is exposed to the outside of the driving-means housing  250  to then be engaged with the extracting screw unit  210  and the extracting case  240 . Meanwhile, a control case  252  and a control panel  253  are disposed at one side of the driving-means housing  250  to control the driving means. 
         [0093]    Hereinafter, the operation of the juice extracting apparatus according to the second embodiment of the present invention will be described with reference to the following drawings. 
         [0094]    As shown in  FIG. 15 , if a raw material is injected into the inlet  201 , the extracting screw unit  210  engaged with the drive shaft  251  of the driving means, thereby slicing the raw material by the screw blade  211 . In addition, the raw material is pulverized and conveyed by a guide protrusion  221  of the rotary extracting net unit  220  rotating in the opposite direction to a direction in which the extracting screw unit  210  rotates. 
         [0095]    Like in the first embodiment of the present invention, the sun gear  212  of the extracting screw unit  210 , the plurality of planet gears  231  of the discharge guide unit  230  and the ring gear  223  of the rotary extracting net unit  220  are engaged with each other. Accordingly, as the extracting screw unit  210  rotates, the rotary extracting net unit  220  rotates in the opposite direction to the direction in which the extracting screw unit  210  rotates. 
         [0096]    Here, a distance between the outer peripheral surface of the extracting screw unit  210  and the inner peripheral surface of the rotary extracting net unit  220  gradually decreases toward a lower end of the extracting screw unit  210 , and the conveyed raw material is compressed therebetween, thereby extracting juice from the raw material. 
         [0097]    If the sludge of the downwardly conveyed raw material is subjected to greater than a predetermined pressure, the pressure of the sludge exceeds elasticity derived from one side  236 - 1  of the guide rubber  236  installed at a lower end of the discharge guide unit  230  to then be discharged to the outside through the sludge outlet  242  of the extracting case  240 . The juice extracted from the raw material flows out through the mesh net  222  of the rotary extracting net unit  220  to then be discharged to the outside through the juice outlet  241  of the extracting case  240 . 
         [0098]    In the above-described procedure, when the rotary extracting net unit  220  rotates, a brush  224  wipes up the inner peripheral surface of the extracting case  240  while making a contact with makes a contact with the inner peripheral surface of the extracting case  240 . 
         [0099]    Meanwhile, while the cleaner  260  rotates together with the rotary extracting net unit  220 , as shown in  FIG. 14 , if the stopper protrusion  266  of the cleaner  260  makes a contact with the hooking portion  246  of the extracting case  240 , the cleaner  260  does not rotate. Accordingly, only the rotary extracting net unit  220  continuously rotates. 
         [0100]    In this state, the cleaner rubber  262  fixed on the inner peripheral surface of the cleaner  260  is elastically bent to remove the sludge sticking on a surface of a bottom end of a mesh net  202  of the rotary extracting net unit  220 . 
         [0101]      FIG. 16  illustrates an interior side of an extracting case  240  of an according to a third embodiment of the present invention,  FIG. 17  is a perspective view of a cleaner  300  shown in  FIG. 16 , and  FIG. 18  is a cross-sectional view of a juice extracting apparatus with cleaner  300  shown in  FIGS. 16 and 17 . Here, a driving means is illustrated in the above drawings. 
         [0102]    The general configuration of the juice extracting apparatus according to the third embodiment of the present invention is substantially the same as that of the juice extracting apparatus according to the second embodiment of the present invention. Therefore, the following description will focus on different structures in both embodiments. In addition, in the following embodiment, components having substantially the same function as the second embodiment are identified by the same reference numerals, and detailed descriptions thereof will be omitted. 
         [0103]    The juice extracting apparatus according to the third embodiment of the present invention features in that the cleaner  260  as one component of the juice extracting apparatus according to the second embodiment of the present invention is replaced with a cleaner  300  having a simplified configuration, as shown in  FIGS. 16 to 18 . 
         [0104]    That is to say, in this embodiment, the cleaner  300  is fixed on a hooking portion  246  of an extracting case  240  and is made of an elastic material. The cleaner  300  includes a fitting portion  310  formed stepwise so as to be fitted into the hooking portion  246  and an extending portion  320  integrally formed with the fitting portion  310  and extending toward the inside of the extracting case  240 . 
         [0105]    When a rotary extracting net unit  220  rotates, the extending portion  320  of the cleaner  300  fixed on the hooking portion  246  of the extracting case  240  is elastically bent while making a contact with the rotary extracting net unit  220 . Accordingly, the extending portion  320  forcibly removes the sludge sticking on a mesh net  222  of the rotary extracting net unit  220 . 
         [0106]    As described above, in the juice extracting apparatuses according to the second and third embodiments of the present invention, since the extracting screw unit and the rotary extracting net unit rotate in a geared manner such that the extracting screw unit rotates in one direction and the rotary extracting net unit rotates in the opposite direction to the direction in which the extracting screw unit rotates, thereby improving juice extracting efficiency, compared to the conventional juice extracting apparatus in which only the screw is rotated. 
         [0107]    In addition, since the extracting screw unit and the rotary extracting net unit rotate in opposite directions, the amount of sludge existing between the extracting screw unit and the rotary extracting net unit can be minimized and an outer surface of the rotary extracting net unit can be automatically cleaned by means of the brush and the cleaner. 
         [0108]    As described above, although exemplary embodiments of the present invention have been described in detail hereinabove, it should be understood that many variations and modifications of the basic inventive concept herein described, which may appear to those skilled in the art, will still fall within the spirit and scope of the exemplary embodiments of the present invention as defined by the appended claims. 
         [0109]    For example, in the juice extracting apparatus according to each of the embodiments of the present invention, a motor being capable of rotating forward and backward can be used as the driving means. When a large amount of raw material is injected into an injection cover for extracting juice therefrom, a large load may be applied to the motor, disabling the motor to properly rotate, thereby lowering juice extracting efficiency. 
         [0110]    In addition, the juice extracting apparatus according to the present invention may further include a sensor sensing a current varying according to the load applied to the drive shaft, that is, the extracting screw unit ( 110  or  220 ) when excessive load is applied to the drive shaft of the driving means (motor), and a controller connecting the sensor and the driving means. The sensor and the controller are well-known components and are not illustrated in the drawings. 
         [0111]    The controller controls the driving motor to stop according to a signal of the sensor indicating a change in the current due to the overload applied to the drive shaft of the motor, to then rotate backward. Therefore, the extracting screw unit ( 110  or  210 ), which is prevented from being rotated by the raw material, rotate in opposite directions, thereby eliminating the load applied to the drive shaft of the motor and caused by the raw material. Thereafter, the controller controls the motor to rotate forward, thereby performing a normal extracting process. 
         [0112]    Although specific embodiments were described herein, it should be understood that many variations and modifications of the basic inventive concept herein described, which may appear to those skilled in the art, will still fall within the spirit and scope of the exemplary embodiments of the present invention as defined by the appended claims. 
         [0113]    The drawings and the forgoing description gave examples of the present invention. The scope of the present invention, however, is by no means limited by these specific examples. Numerous variations, whether explicitly given in the specification or not, such as differences in structure, dimension, and use of material, are possible. The scope of the invention is at least as broad as given by the following claims.