Patent Publication Number: US-7905198-B2

Title: Ascent and descent apparatus for liquid material spray printer

Description:
TECHNICAL FIELD 
     The present invention relates to an ascent and descent apparatus for a liquid material spray printer, and more particularly to an ascent and descent apparatus for a liquid material spray printer, which may control a distance between a subject to be coated and a spray assembly optimally. 
     BACKGROUND ART 
     Generally, a liquid material spray printer is a device for coating liquid material on a surface of a subject to print a predetermined image. As an example of such a liquid material spray printer, there is an ink-jet printer that may coats an ink material for printing. 
     The liquid material spray printer includes a transferring table on which a subject to be coated is mounted, a transferring device for reciprocating the transferring table so that liquid material may be coated on the subject, an ascent and descent device for ascending/descending the transferring device to a height suitable for liquid material coating, and a spray assembly installed at a substantial center of the transferring device to be capable of reciprocating in a direction perpendicular to a moving direction of the transferring table. The spray assembly contains liquid material and is provided with a nozzle capable of spraying the liquid material to the subject to be coated. 
     The ascent and descent device is a device that lifts a subject transferred below the spray assembly by the transferring device to a height suitable for printing liquid material. Such an ascent and descent device is disclosed in Korean Utility Model Registration Nos. 20-0300098, 20-0292979 and 20-0290203. 
     The ascent and descent device includes a base plate, a lead screw rotatably installed along a length of the base plate and having threads in opposite directions based on a center point, a transferring block screwed to the lead screw and selectively reciprocating within a predetermined range by rotation of the lead screw, a guide bar installed to both sides of the lead screw to guide reciprocation of the transferring block and capable of being inserted into the transferring block, and a crosslink having one end supporting a predetermined flat table and the other end to which a pair of unit links hinged to the transferring block are hinged at their center so as to lift the flat table as the transferring block is reciprocating. 
     However, as described above, the ascent and descent device requires many components, so much cost is needed to manufacture and assemble the components. In particular, the ascent and descent device is not suitable for lifting a flat table with a large size since only one crosslink is installed to the lead screw. That is to say, in order to apply such an ascent and descent device to a flat table with a large size, such devices should be installed at several positions so that the flat table may be stably supported and lifted. However, using several ascent and descent devices deteriorates productivity of the liquid material spray printer and causes increase of its price. Thus, there is needed an ascent and descent device that may lift a flat table with a large size more effectively. 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     The present invention is designed to solve the problems of the prior art, and therefore an object of the invention is to provide an ascent and descent apparatus for a liquid material spray printer, which may lift a flat table using simple components in an effective way. 
     Another object of the invention is to provide an ascent and descent apparatus that may be effectively applied to a flat table with a large size. 
     TECHNICAL SOLUTION 
     In order to accomplish the above object, the present invention provides an ascent and descent apparatus for a liquid material spray printer, which includes a sliding member having a pair of sliders selectively reciprocating in opposite directions by a driving unit; a frame installed above the sliders and having an elongated guide hole formed at a position corresponding to a reciprocating range of the sliders; and a pair of crosslink members installed to an upper surface of the frame to be respectively coupled with the pair of sliders through the elongated guide hole, the crosslink members having an upper end that supports a predetermined flat table, wherein the crosslink members include a pair of unit links that are hinged at a substantial center thereof, in which a lower end of one of the pair of unit links is coupled to the slider and a lower end of the other of the pair of unit links is hinged to the frame, in which an upper end of one of the pair of unit links is hinged to the flat table and an upper end of the other of the pair of unit links supports the flat table rotatably, whereby the flat table is lifted by means of reciprocation of the sliders. 
     Preferably, the pair of sliders are installed with a predetermined interval therebetween and have rack gears formed on sides thereof facing with each other, the driving unit includes a pinion gear in the predetermined interval so that the pinion gear is engaged with the rack gear, and the pair of sliders are reciprocated in opposite directions by means of rotation of the pinion gear. 
     More preferably, the crosslink members further include another pair of unit links connected to the pair of unit links by means of a connection member so that two pairs of unit links support the flat table. 
     In addition, it is preferred that the sliding member further includes a support roller installed in the reciprocating range so as to support reciprocation of the sliders. 
     Moreover, it is also preferred that the sliding member further includes a sensor for sensing reciprocation of the sliders; and a controller for controlling operation of a driving motor according to a signal from the sensor, whereby the reciprocating range of the sliders is selectively controlled. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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: 
         FIG. 1  is a perspective view showing a liquid material spray printer to which an ascent and descent apparatus for a liquid material spray printer according to a preferred embodiment of the present invention is installed; 
         FIG. 2  is a perspective view showing an ascent and descent apparatus for a liquid material spray printer according to a preferred embodiment of the present invention; 
         FIG. 3  is a bottom view of  FIG. 2 ; 
         FIG. 4  is an exploded perspective view of  FIG. 3 ; and 
         FIG. 5  is a sectional view taken along V-V′ line of  FIG. 2 . 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     The present invention will be described in detail referring to the drawings the terms used should not be construed as limited to general and dictionary meanings but based on the meanings and concepts of the invention on the basis of the principle that the inventor is allowed to define terms appropriate for the best explanation. Therefore, the description herein the scope of the invention be understood that other and modifications could be made thereto without departing from the spirit and scope of the invention. 
     The present invention relates to an ascent and descent apparatus for a liquid material spray printer, which lifts a flat table to which a subject to be coated is mounted to a height suitable for coating liquid material.  FIG. 1  is a perspective view showing a liquid material spray printer to which an ascent and descent apparatus for a liquid material spray printer according to a preferred embodiment of the present invention is installed, and  FIG. 2  is a perspective view showing an ascent and descent apparatus for a liquid material spray printer according to a preferred embodiment of the present invention. In addition,  FIG. 3  is a bottom view of  FIG. 2 , and  FIG. 4  is an exploded perspective view of  FIG. 3 . 
     Referring to  FIGS. 1 to 4 , the ascent and descent apparatus  100  for a liquid material spray printer includes a driving unit  10 , a sliding member  20  having a pair of sliders  22  reciprocated by the driving unit  10 , a frame  30  installed above the sliding member  20 , and a pair of crosslink members  50  installed to the upper surface of the frame  30  and respectively coupled to the pair of sliders  22  to lift a flat table  80 . 
     The driving unit  10  includes a driving motor  12 , and a gear assembly  14  for transferring a driving force of the driving motor  12 . The driving motor  12  is commonly used and preferably controlled by a controller (not shown), described later. 
     The gear assembly  14  includes a worm  15  connected to the driving motor  12 , a worm wheel  16  converting rotational force of the worm  15  into vertical movement, and a pinion gear  17  integrated with the worm wheel  16 . The pinion gear  17  is installed between the pair of sliders  22  to give a driving force to the pair of sliders  22  respectively. Meanwhile, the worm  15  and the worm wheel  16  have common configurations. 
     The sliding member  20  includes an upper plate  23 , a lower plate  24 , and a pair of sliders  22  installed between the upper and lower plates  23 ,  24  and reciprocating in opposite directions by the driving unit  10 . 
     The upper and lower plates  23 ,  24  are installed with a predetermined interval and support reciprocation of the sliders  22 . The lower plate  24  is installed to the lower surface  32  of the frame  30 , while the upper plate  23  is installed with a space that substantially allows reciprocation of the sliders  22 . The upper and lower plates  23 ,  24  are coupled to each other by means of a coupling member  24  such as a screw. 
     The pair of sliders  22  are installed with a predetermined intervals on the center of the pinion gear  17 , and rack gears  22   a  to be engaged with the pinion gear  17  are formed on their sides facing with each other. That is to say, since the pinion gear  17  and the rack gear  22   a  are engaged with each other, as the pinion gear  17  rotates, the pair of sliders  22  rotate in opposite directions. 
     The slider  22  has a coupling groove  22   b  for coupling with the crosslink member  50 . The coupling groove  22   b  is formed at a predetermined position of the slider  22  so that a coupling member  22   c  is installed therein to couple the crosslink member  50  and the slider  22 . Preferably, a spiral ridge is formed on an inner surface of the coupling groove  22   b  to allow screwing. 
     Preferably, the sliding member  20  includes a support roller  27  supporting reciprocation of the slider  22 . More preferably, the support roller  27  includes a first support roller  27   a  for supporting a side  22   d  of the slider  22 , and a second support roller (not shown) for supporting an upper surface  22   e  and a lower surface  22   f  of the slider  22 . 
     The first support roller  27   a  supports the side of the slider  22  to prevent the slider  22  from shaking right and left. Preferably, at least two first support rollers  27   a  are installed in the reciprocating range. It makes the pair of sliders  22  reciprocate in parallel with each other. 
     The second support roller (not shown) is installed to the upper and lower plates  23 ,  24  to support the upper and lower surfaces of the slider  22 , and prevents the slider  22  from shaking up and down. Preferably, at least two second support rollers are installed in the reciprocating range. It allows the pair of sliders  22  to reciprocate in parallel with each other. 
     Preferably, the sliding member  20  includes sensors  28  for sensing reciprocation of the slider  22 , and a controller (not shown) for controlling operation of the driving motor  12  according to a signal from the sensors  28 . 
     The sensors  28  are installed at a predetermined position in the reciprocating range. The sensors  28  detect a protrusion  29  protruded from the slider  22  to sense reciprocation of the slider  22 . Thus, the reciprocating range of the slider  22  may be controlled by adjusting a distance between the sensors  28 . 
     The frame  30  is installed in contact with the lower plate  24 , and has an elongated guide hole  34  formed at a position corresponding to the reciprocating range of the slider  22 . As shown in  FIGS. 2 and 3 , the elongated guide hole  34  is formed along a moving direction of the slider  22  so that the coupling member  22   c  for coupling the slider  22  and the crosslink member  50  is inserted and installed therein. 
     The crosslink member  50  is coupled to the slider  22  through the elongated guide hole  34 , and its upper end is installed to the upper surface of the frame  30  to support a predetermined flat table  80 . 
     The crosslink member  50  includes a pair of unit links  52 ,  54  hinged with each other at its substantial center. The pair of unit links  52 ,  54  include a first unit link  52  having a lower end  52   a  coupled to the slider  22  and an upper end  52   b  supporting the flat table  80 , and a second unit link  54  having a lower end  54   a  hinged to the frame  30  and an upper end  54   b  supporting the flat table  80 . 
     One of the upper ends  52   b ,  54   b  of the first and second unit links  52 ,  54  is hinged to the flat table  80 , and the other slidably supports the flat table  80 . One of the upper ends  52   b ,  54   b  hinged to the table  80  is used for fixing the flat table  80 , and the other slidably supporting the flat table  80  is used for lifting the flat table  80 . Preferably, sliding rollers  55  are installed to the lower end  52   a  of the first unit link  52  and a sliding one among the upper ends  52   b ,  54   b  of the first and second unit links  52 ,  54 . 
     The crosslink member  50  configured as above is slid as the slider  22  is reciprocating, thereby lifting the flat table  80  installed to its upper end. 
     Preferably, the crosslink member  50  further includes a pair of unit links  58 ,  59  connected to the pair of unit links  52 ,  54  by means of a connection member  57 . That is to say, two pairs of unit links  52 ,  54 ,  58 ,  59  support the flat table  80 . 
     More preferably, the crosslink member  50  includes connectors  56  interposed in a coupling portion with the slider  22  so that the unit links may be smoothly slid, as shown in  FIGS. 2 and 3 . The connectors  56  are respectively coupled to the slider  22  and the connection member  57  by using the coupling member  22   c.    
     As mentioned above, the ascent and descent apparatus  100  for a liquid material spray printer according to the present invention may lift the flat table  80  effectively by using a simple configuration composed of the driving unit  10 , the sliding member  20 , the frame  30  and the crosslink member  50 . In addition, since a pair of crosslink members  50  are operated at the same time by one driving motor  12 , the apparatus of the present invention may be effectively applied to a flat plate with a large size. 
     Now, operation of the ascent and descent apparatus for a liquid material spray printer according to a preferred embodiment of the present invention will be described with reference to  FIGS. 1 to 5 . The ascent and descent apparatus  100  is installed to a liquid material spray printer  200  and works together with it, so the operation of the liquid material spray printer  200  is described together. 
     First, a subject (not shown) to be coated is mounted to the upper surface of a transferring table  60 . The transferring table  60  is a metal flat plate reciprocating within a predetermined range by a transferring device  62 . In its lower surface, a sub rack gear  61  to be engaged with a sub pinion gear  63  of the transferring device  62  and a metal guide member  65  guiding movement of the transferring table  60  are respectively installed. 
     The subject to be coated is preferably installed at a position corresponding to a concave groove  66  formed on the guide member  65 . In this case, a sensor  82  may sense position of the subject and allow controlling operation of a spray assembly  70 . 
     Subsequently, if a worker pushes an operation switch (not shown), a driving force is transferred to the sub pinion gear  63  and the sub rack gear  61  so that the transferring table  60  is moved below the spray assembly  70 . That is to say, the transferring table  60  is moved to a position where the spray assembly  70  may print an image on the subject. 
     After the subject is moved below the spray assembly  70 , a controller (not shown) and a height sensor  83  detect an actual distance between the spray assembly  70  and the upper surface of the subject, and then compares it with a predetermined optimal coating distance. 
     The ascent and descent apparatus  100  lifts the flat table  80  as much as a difference between the actual distance and the optimal coating distance. That is to say, the height sensor  83  and the controller control the subject to be lifted to the optimal coating distance. 
     After the coating distance is controlled optimally by the ascent and descent apparatus  100 , the spray assembly  70  starts printing. As the printing work is progressed, the transferring table  60  moves at a predetermined speed. 
     Meanwhile, the flat table  80  is provided with a support roller  67  and guide rollers  86 ,  87  that support the transferring table  60 . 
     The support roller  67  is a roller with a predetermined magnetism, and it is coupled to the metal transferring table  60  by magnetic force so as to prevent the transferring table  60  from shaking during movement. 
     The guide rollers  86 ,  87  are composed of two rollers installed at a predetermined interval between them. One of the guide rollers has a predetermined magnetism, and the interval is defined so that the guide member  66  may substantially pass through it with being guided. Since the metal guide member  66  moves in close contact with the roller having magnetism, it is possible to prevent the transferring table  60  from shaking during movement. Thus, an image may be printed in an exact and precise way. 
     The printing work comes to an end when the sensor  82  detects the concave groove  66  formed at a position corresponding to an end of the subject. That is to say, if the sensor  82  senses the concave groove  66 , the controller stops liquid material coating and restores a nozzle to its initial position. 
     Subsequently, if a second sensing member  89   a  detects a first protrusion  69 , the controller stops transferring a driving force so that the transferring table  60  stops advancing. Subsequently, the driving motor (not shown) transfers a driving force reversely so that the transferring table  60  moves rearward to a printing start position. The rearward movement of the transferring table  60  is stopped when a first sensing member  89  detects a second protrusion  69   a.    
     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 
     As described above, the ascent and descent apparatus for a liquid material spray printer according to the present invention gives the following effects. 
     First, the ascent and descent apparatus for a liquid material spray printer may lift a flat table effectively by using simple components. 
     Second, the ascent and descent apparatus for a liquid material spray printer may be effectively applied to a flat table with a large size.