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CLAIM OF PRIORITY 
     This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from my applications entitled  OPENING AND CLOSING APPARATUS FOR AIR DISCHARGE PORT OF AIR CONDITIONER  filed with the Korean Industrial Property Office on Jun. 12, 2000 and there duly assigned Ser. Nos. 2000/32179 and 2000/32180. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to air outlet opening apparatus for air conditioners, and more particularly to an air outlet opening apparatus for air conditioners, which is capable of being smoothly operated without laterally tilting its shutter. 
     2. Description of the Prior Art 
     In the housing of the air conditioner body of a general air conditioner are formed an air inlet for sucking indoor air and an air outlet for exhausting air-conditioned air into an indoor space. A heat exchanger for exchanging heat with sucked air and a fan for blowing air from the heat exchanger to the air outlet are mounted in the air conditioner body of the air conditioner. Recently, in order to prevent dust or impurities from entering the air conditioner body through the air outlet, an air outlet opening apparatus for selectively opening and closing the air outlet is generally provided in the air conditioner body of the air conditioner. 
     As illustrated in FIG. 1, a conventional air outlet opening apparatus for air conditioners includes a shutter  3  having a size sufficient to selectively open and close the air outlet  2  formed in the front panel  1  of an air conditioner body, a pair of support plates for guiding the movement of the shutter  3  as well as supporting the shutter  3 , and elevation means for selectively elevating and lowering the shutter. 
     An upper guide groove  6   a  and a lower guide groove  6   b  are formed on the inner side surface of each of the support plates  4   a  and  4   b  situated beside the air outlet  2 . Two guide pins  7   a  and  7   b  are formed on each of the outer side surfaces of the shutter  3  to guide the movement of the shutter  3  while being fitted into the upper and lower guide grooves  6   a  and  6   b.    
     The elevation means includes an elevation member  5  provided with a rack gear portion  5   a , a pinion gear  8  engaged with the rack gear portion  5   a  of the elevation member  5 , and a drive motor  9  for driving the pinion gear  8 . The elevation member  5  is attached to the central portion of the rear surface of the shutter  3 . The drive motor  9  assembled with the pinion gear  8  is secured to the rear surface of the front panel  1 . In this case, the pinion gear  8  is engaged with the rack gear portion  5   a  of the elevation member  5 . 
     In the conventional air outlet opening apparatus for air conditioners, as the pinion gear  8  is rotated by the operation of the drive motor  9 , the elevation member  5  is elevated. Accordingly, the shutter  3  secured to the elevation member  5  is elevated while being guided by the guide grooves  6   a  and  6   b  of the support plates  4   a  and  4   b , thereby selectively opening and closing the air outlet  2  of the front panel  1 . 
     In the conventional air outlet opening apparatus, a single elevation member  5  is secured to the center portion of the shutter  3 , so the shutter  3  is laterally tilted by the vibration of the apparatus. As a result, the shutter is not elevated smoothly and, consequently, the guide grooves  6   a  and  6   b  and the guide pins  7   a  and  7   b  are worn out. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide an air outlet opening apparatus for air conditioners, which is capable of selectively elevating and lowering its shutter at two horizontally spaced positions, thereby smoothly performing the elevation and lowering of its shutter and the opening and closing of the air outlet. 
     In order to accomplish the above object, the present invention provides an air outlet opening apparatus for air conditioners, including: a shutter for selectively opening and closing the air outlet formed on an air conditioner body; a pair of support plates mounted beside the shutter to guide the elevation and lowering of the shutter; and elevation means for selectively elevating and lowering the shutter; wherein the elevation means includes a pair of elevation members positioned to be slid on the support plates, a drive motor for generating power to move the elevation members, and power transmission means for converting the rotating movement of the drive motor to the simultaneous linear movements of the elevation members. 
     The power transmission means can include two rack gear portions formed on the elevation members, a pair of pinion gears, one of which is engaged with the drive motor, engaged with the rack gear portions, and a common shaft connecting the pinion gears. 
     The elevation means can further include guide grooves formed longitudinally on the support plates and two pairs of support pins each mounted on both sides of the shutter while being spaced apart from each other and inserted into the guide grooves while passing through the elevation members. 
     The guide grooves can include first and second guide grooves which partially overlap each other to communicate with each other, and the support pins can include first and second support pins which are inserted into the first and second guide grooves, respectively. 
     The guide grooves may be comprised of first and second guide grooves which partially overlap each other to communicate with each other, and the support pins may be comprised of first and second support pins which are inserted into the first and second guide grooves, respectively. 
     The first and second guide grooves may be formed to have different depths, and the first and second support pins may be formed to have lengths corresponding to the depths of the first and second guide grooves. 
     The first guide groove may be formed to have a relatively narrow width and a relatively deep depth, the second guide groove may be formed to have a relatively wide width and a relatively shallow depth, and the first and second support pins may be formed to have widths and lengths corresponding to the widths and depths of the first and second guide grooves. 
     The first and second guide grooves may each have a vertical groove portion that is connected to a horizontal groove portion extending toward the air outlet at its upper end to guide the first and second guide pins, and the elevation members may be each provided with upper and lower inclined slots to guide the support pins through the horizontal groove portions when the support pins reach the horizontal groove portions. 
     The upper inclined slot may have a vertical extension at its lower end and the lower inclined slot may be formed to be longer than the upper inclined slot, and the first support pin inserted into the upper inclined slot may be situated behind the second support pin inserted into the lower inclined slot in the anteroposterior direction of the shutter. 
     The common shaft may have a polygonal sectional shape to minimize its twisting. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete appreciation of the invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein: 
     FIG. 1 is an exploded perspective view showing a conventional air outlet opening apparatus for air conditioners; 
     FIG. 2 is a cross section showing the structure of an air conditioner body in accordance with an embodiment of the present invention; 
     FIG. 3 is an exploded perspective view showing the air outlet opening apparatus of the embodiment of FIG. 2; 
     FIG. 4 is a detailed view showing a section of FIG. 3; 
     FIGS. 5,  6  and  7  are cross sections showing the operation of the air outlet opening apparatus of the first embodiment of FIGS. 2 and 3; 
     FIG. 8 is a detailed view showing the important section of FIG. 7; 
     FIG. 9 is a cross section taken along line A-A′ of FIG. 7; 
     FIG. 10 is a cross section showing guide grooves and support pins in accordance with another embodiment of the present invention; and 
     FIGS. 11 and 12 are cross sections showing another air conditioner body in accordance with another embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference now should be made to the drawings, in which the same reference numerals are used throughout the different drawings to designate the same or similar components. 
     As illustrated in FIG. 2, an air conditioner of the present invention includes an air conditioner body  10  that includes a box-shaped casing  11  and a front panel  12  for covering the open front of the casing  11 . A heat exchanger  15  for performing heat exchange and a fan  16  for blowing air are mounted in the interior of the air conditioner body  10 . An air outlet  13  for exhausting air-conditioned air to an indoor space and an air inlet  14  for sucking indoor air into the interior of the air conditioner body  10  are formed in the upper and lower portions of the front panel  12 , respectively. 
     A plurality of wind direction adjusting blades  17  for adjusting the direction of exhausted air are situated at positions that are inwardly spaced apart from the air outlet  13 . An air outlet opening apparatus  20  of the present invention is mounted in front of the wind direction adjusting blades  17 . The shutter  21  of the air outlet opening apparatus  20  selectively opens and closes the air outlet  13  while being selectively elevated and lowered along guide grooves  25  and  26  provided beside the air outlet  13 . 
     The air outlet opening apparatus of the present invention is characterized in that the shutter  21  can be elevated and lowered by applying force to the shutter  21  in two positions so as to allow the shutter  21  to be smoothly elevated and lowered. 
     As shown in FIGS. 3 and 4, a pair of support plates  22   a  and  22   b  are longitudinally disposed along both sides of the inner surface of a front panel  12  beside the air outlet  13  formed in the front panel  12  to support and guide the movement of the shutter  21 . A depression  23  is longitudinally formed on the inner surface of each of the support plates  22   a  and  22   b , and two guide grooves  25  and  26  are formed on the depression  23  to guide support pins  24   a  and  24   b  that are connected to one side of the shutter  21 . 
     Two elevation members  27   a  and  27   b  are each positioned in the depression  23  so as to be selectively elevated and lowered to selectively elevate and lower the shutter  21 . Two cover plates  28   a  and  28   b  are attached to the support plates  22   a  and  22   b  to support the shutter  21 . A guide cutout  29  is formed in each of the cover plates  28   a  and  28   b  to correspond to one of the guide grooves  25   a  and  26   a.    
     A rack gear portion  30  is formed on one side of each of the elevation members  27   a  and  27   b . Two pinion gears  31   a  and  31   b  are situated to be engaged with the rack gear portions  30  of the elevation members  27   a  and  27   b , respectively. The two pinion gears  31   a  and  31   b  are connected by a horizontal common shaft  34  to be rotated at the same time. The pinion gear  31  a is engaged with the gear  33  of a drive motor  32 . Accordingly, the air outlet opening apparatus of the present invention is constructed so that the pinion gears  31   a  and  31   b  are rotated by the operation of the drive motor  32  and the elevation members  27   a  and  27   b  are elevated or lowered by the rotation of the pinion gears  31   a and  31   b . That is, the two pinion gears  31   a  and  31   b  are simultaneously rotated by the operation of the drive motor  32 , thereby allowing the two elevation members  27   a  and  27   b  to be elevated or lowered at the same time. In this case, the common shaft  34  of the pinion gears  31   a  and  31   b  preferably has a polygonal sectional shape so as to minimize its twisting. 
     Two pairs of support pins are each situated beside the shutter  21 . Each pair of support pins includes an upper support pin  24   a  and a lower support pin  24   b , and the upper and lower support pins  24   a  and  24   b  are upwardly spaced apart from each other. Each of the support pins  24   a  and  24   b  passes through one of the cover plates  28   a  and  28   b  and one of the elevation members  27   a  and  27   b , and is inserted into one of the guide grooves  25  and  26  of the support plates  22   a  and  22   b . Accordingly, while the elevation members  27   a  and  27   b  are elevated or lowered, the support pins  24   a  and  24   b  are moved along the guide grooves  25  and  26  formed in the support plates  22   a  and  22   b . That is, the elevation members  27   a  and  27   b  force the support pins  24   a  and  24   b  to be elevated or lowered. 
     As shown in FIGS. 8 and 9, each pair of guide grooves formed on each of the support plates  22   a  and  22   b  includes a first guide groove  25  and a second guide groove  26 . The first guide groove  25  consists of a vertical groove portion  25   a  longitudinally extended on one of the support plates  22   a  and  22   b  and a horizontal groove portion  25   b  transversely extended from the upper end of the vertical groove portion  25   a  on one of the support plates  22   a  and  22   b ; while the second guide groove  26  consists of a vertical groove portion  26   a  longitudinally extended on one of the support plates  22   a  and  22   b  and a horizontal groove portion  26   b  transversely extended from the upper end of the vertical groove portion  26   a  on one of the support plates  22   a  and  22   b . The vertical groove portions  25   a  and  26   a  serve to guide the elevation and lowering of the first and second support pins  24   a  and  24   b , respectively. The horizontal groove portions  25   b  and  26   b  serve to guide the first and second support pins  24   a  and  24   b  so that the shutter  21  is somewhat projected trough the air outlet  13  by allowing the first and second support pins  24   a  and  24   b  to move forward when the first and second support pins  24   a  and  24   b  reach the upper ends of the vertical groove portions  25   a  and  26   a , respectively. 
     The lower end of the first guide groove  25  and the upper end of the vertical groove portion of the second guide groove  26  coincide with each other, thus causing the first and second guide grooves  25  and  26  to be connected to each other. However, the first support pin  24   a  is moved along only the first guide groove  25  and the second support pin  24   b  is moved along only the second guide groove  26 , so the support pins  24   a  and  24   b  are moved smoothly. To this end, as shown in FIG. 9, the first and second guide grooves  25  and  26  are formed to have different depths and the first and second support pins  24   a  and  24   b  are formed to have different lengths. In more detail, the first guide groove  25  is formed to have a relatively deep depth, whereas the second guide groove  26  is formed to have a relatively shallow depth. The portion of the first support pin  24   a  inserted into the first guide groove  25  is formed to have a relatively long length, while the portion of the second support pin  24   b  inserted into the second guide groove  26  is formed to have a relatively short length. 
     FIG. 10 is a cross section showing guide grooves and support pins in accordance with another embodiment of the present invention. In this embodiment, the depths of the first and second guide grooves  25  and  260  are different, the lengths of the first and second support pins  24   a  and  240   b  are different, the width of the second guide groove  260  is larger than that of the first guide groove  25 , and the outer diameter of the second support pin  240   b  inserted into the second guide groove  260  is larger than that of the first support pin  24   a  to correspond to the width of the second guide groove  260 . This construction allows the support pins  25  and  260  to be smoothly elevated or lowered, and prevents the support pins  25  and  260  from being wrongly assembled. 
     Referring to FIGS. 4 and 8, an upper inclined slot  35  and a lower inclined slot  36  are formed on each of the elevation members  27   a  and  27   b  at positions where the support pins  24   a  and  24   b  pass through the elevation member  27   a  or  27   b . The inclined slots  35  and  36  serve to cause the support pins  24   a  and  24   b  to be moved along the horizontal groove portions  25   b  and  26   b  when the support pins  24   a  and  24   b  are upwardly moved along the vertical groove portions  25   a  and  26   a  and reach the horizontal groove portions  25   b  and  26   b  by the elevation of the elevation members  27   a  and  27   b.    
     In this case, the upper inclined slot  35  has a vertical extension  35   a  that is downwardly extended from its lower end, and the lower inclined slot  36  is formed to have a length larger than that of the upper inclined slot  35 . Two connecting bars  37  are attached to both side ends of the shutter  21 . Two projections  37   a  and  37   b  are formed on each of the connecting bars  37  in upper and lower positions to hold the first and second support pins  24   a  and  24   b . The upper projection  37   a  connected to the first support pin  24   a  is situated in a rear position, while the lower projection  37   b  connected to the second support pin  24   b  is situated in a front position. The horizontal groove portion  25   b  of the first guide groove  25  is formed to be shorter than that of the horizontal groove portion  26   b  of the second guide groove  26 . 
     In this construction, the first support pin  24   a  is situated behind the second support pin  24   b  on the side of the shutter  21 , so the first and second support pins  24   a  and  24   b  are engaged with the upper and lower inclined grooves  35  and  36  without hindrance. Additionally, this construction allows the shutter  21  to be closed, in such a way that the front surface of the shutter  21  is situated in the same plane that the front surface of the front panel  12  forms and a position difference t is maintained between the first and second support pins  24   a  and  24   b , when the shutter  21  is completely closed by the elevation of the elevation members  27   a  and  27   b . When the shutter  21  is opened by the lowering of the elevation members  27   a  and  27   b , the shutter  21  is first opened on its lower portion and the shutter  21  is forwardly inclined, thereby allowing the lowering of the shutter  21  to be performed smoothly. 
     In particular, this construction, as illustrated in FIG. 11, causes the opening and closing of the shutter  21  to be performed smoothly when the front panel  12  of the air conditioner body  10  is curved. In this case, when the horizontal groove portion  26   b  of each second guide groove  26  and the lower inclined slot  36  of each elevation member  27   a ,  27   b  is formed to have a length greater than usual and the position difference t between the first and second support pins  24   a  and  24   b  is enlarged, the shutter  21  is closed with its front surface situated in the same plane as the front surface of the front panel  12  forms. Additionally, as shown in FIG. 12, when the shutter  21  is opened by the lowering of the elevation members  27   a  and  27   b , the lower portion of the shutter  21  is first opened, thus allowing the lowering of the shutter  21  to be smoothly performed. 
     In addition, an interval between the upper horizontal groove portion  25   b  and the lower horizontal groove portion  26   b  should coincide with an interval between the first and second support pins  24   a  and  24   b  in order to cause the above operations to be smoothly performed. 
     The operation of the air outlet opening apparatus of the present invention is described, hereinafter. 
     As shown in FIG. 5, when the air outlet  13  of the air conditioner body  10  is opened, the elevation member  27   a  is situated on the lower portion of the support plate  22   a , and the support pins  24   a  and  24   b  are also situated on the lower portion of the support plate  22   a  while being present in the vertical groove portions  25   a  and  26   a  of the first and second guide grooves  25  and  26 , respectively. The support pins  24   a  and  24   b  are prevented from being laterally displaced by the guidance of the vertical groove portions  25   a  and  26   a , and the elevation member  27   a  is prevented from being laterally displaced by the presence of the elevation member  27   a  in the depression  23 . At this time, the support pins  24   a  and  24   b  are situated in the upper portions of the upper and lower inclined slots  35  and  36  of the elevation member  27   a , respectively. The support pins  24   a  and  24   b  are situated in the vertical groove portions  25   a  and  26   a , so the upper portion of the shutter  21  is tilted toward the air outlet  13  at a predetermined angle θ. 
     In this state, when the pinion gear  31  a engaged with the rack gear portion  30  of the elevation member  27   a  is rotated by the operation of the drive motor  32 , the elevation member  27   a  is elevated, as illustrated in FIG.  6 . At this time, the support pins  24   a  and  24   b  are elevated by the pushing of the elevation member  27   a , and the shutter  21  secured to the support pins  24   a  and  24   b  is elevated at the same time. Thereafter, when the first and second support pins  24   a  and  24   b  reach the upper ends of the vertical groove portions  25   a  and  26   a  of the first and second guide grooves  25  and  26 , the support pins  24   a  and  24   b  are not elevated any more, but are moved along the horizontal groove portions  25   b  and  26   b  of the first and second guide grooves  25  and  26 . 
     If the elevation member  27   a  is elevated further when the first and second support pins  24   a  and  24   b  reach the upper ends of the vertical groove portions  25   a  and  26   a  of the first and second guide grooves  25  and  26 , the support pins  24   a  and  24   b  are pushed by the upper and lower inclined slots  35  and  36  formed in the elevation member  27   a  and moved toward the air outlet  13  along the vertical groove portions  25   b  and  26   b  of the first and second guide grooves  25   a  and  26   a . When the upper end of the elevation member  27   a  reaches the upper end of the depression  23 , the support pins  24   a  and  24   b  are situated near to the air outlet  13  and in the lower portions of the upper and lower inclined slots  35  and  36 . 
     As shown in FIG. 6, if the elevation member  27   a  is elevated further when the first support pin  24   a  reaches the end of the vertical groove portion  25   b  of the upper guide groove  25 , the first support pin  24   a  stops horizontal movement and, consequently, the horizontal movement of the upper portion of the shutter  21  is stopped. However, the first support pin  24   a  is guided into the vertical extension  35   a  and, thereby, the elevation member  27   a  is elevated further. At this time, the second support pin  24   b  is in the middle of the lower inclined slot  36 , so the second support pin  24   b  can be horizontally moved further. As shown in FIG. 7, when the elevation member  27   a  is completely elevated, the lower end of the shutter  21  coincides with the lower end of the air outlet  13 , thereby allowing the shutter  21  to be situated in the same plane that the front panel  12  forms. The lower portion of the shutter  21  is closed later than the upper portion of the shutter  21 . 
     In order to open the closed shutter  21 , the pinion gear  31   a  is rotated in the opposite direction by the operation of the drive motor  32 , thus lowering the elevation member  27   a . The support pins  24   a  and  24   b  are inwardly pushed by the two inclined slots  35  and  36  of the elevation member  27   a , resulting in being opened while being moved to the interior of the air conditioner body  10  along the horizontal groove portions  25   b  and  26   b  of the guide grooves  25  and  26 . In this case, the lower portion of the shutter  21  is first opened owing to difference between the upper and lower inclined grooves  35  and  36  and difference in the arrangement of the support pins  24   a  and  24   b.    
     If the elevation member  27   a  is further lowered when the support pins  24   a  and  24   b  reach the vertical groove portions  25   a  and  26   a  of the guide grooves  25  and  26  and are situated in the upper portions of the inclined slots  35  and  36 , the support pins  24   a  and  24   b  are lowered along the vertical groove portions  25   a  and  26   a  of the guide grooves  25  and  26 , thereby causing the air outlet  13  of the front panel  12  to be completely opened. The opening of the shutter  21  is performed in the reverse manner of the closing of the shutter  21 . 
     Meanwhile, during the opening and closing of the shutter  21 , the first and second support pins  24   a  and  24   b  having different lengths are moved along the first and second guide grooves  25  and  26  having different depths, so the shutter  21  is smoothly elevated and lowered. 
     When the shutter  21  is closed or opened, the two pinion gears  31   a  and  31   b  are rotated at the same time because the gears  31   a  and  31   b  are connected by the common shaft  34 . Subsequently, the two elevation members  27   a  and  27   b  are selectively elevated and lowered by the operation of the pinion gears  31   a  and  31   b  at the same time. Accordingly, since in the air outlet opening apparatus of the present invention the shutter  21  is selectively opened and closed by the simultaneous elevation and lowering of the two elevation members  27   a  and  27   b  mounted beside the shutter  21 , the shutter  21  is selectively opened and closed smoothly and precisely. 
     As described above, the present invention provides an air outlet opening apparatus for air conditioners, which is capable of selectively elevating and lowering its shutter smoothly without the lateral tilt of the shutter because the shutter is selectively elevated and lowered by two elevation members mounted beside the shutter. 
     In addition, the elevation and lowering of the shutter are guided by the vertical groove portions formed on support plates and the opening and closing of the shutter are guided by the horizontal groove portions formed on the support plates and inclined slots formed in the elevation members, so the opening and closing of the shutter is performed precisely. 
     Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Summary:
An air outlet opening apparatus for air conditioners is provided. The air outlet opening apparatus includes a shutter for selectively opening and closing the air outlet formed on an air conditioner body. A pair of support plates is mounted beside the shutter to guide the elevation and lowering of the shutter. The air outlet opening apparatus further includes elevation means for selectively elevating and lowering the shutter. The elevation means includes a pair of elevation members positioned to be slid on the support plates, a drive motor for generating power to move the elevation members, and power transmission means for converting the rotating movement of the drive motor to the simultaneous linear movements of the elevation members.