Abstract:
A front-edge paper feeding device is applicable for automatically conveying a stack of cardboards one by one. During operation, the stack of cardboards is placed on a grid plate, and a control element is provided for controlling the grid plate to elevate and descend reciprocally. When the grid plate elevates, the cardboards are separated from a conveyor wheel. When the grid plate descends, the conveyor wheel is exposed, such that the conveyor wheel is in contact with the cardboard. A servomotor is provided for controlling intermittent rotations of the transmission shaft while driving the conveyor wheel, so that the conveyor wheel drives the cardboard to move in order to convey and output the cardboard smoothly.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a paper feeding device, in particular to a front-edge paper feeding device applicable for automatically and quickly conveying stacked cardboards at a front edge of different operating procedures. 
     BACKGROUND OF THE INVENTION 
     At present, corrugated cardboards are used extensively in our daily life for carrying, protecting, transporting, and storing objects. In the manufacture of corrugated cardboards, folding, preheating, corrugated molding, gluing, cooling, line pressing, trimming, cutting and stacking processes are used for making the corrugated cardboards, so that the corrugated cardboards can further be manufactured to produce cartons, paperboards and various forms of products for different purposes. 
     In a conventional front-edge paper feeding device of a corrugated carton machine, the paper feeding operation includes the steps of: continuously sucking and pulling the bottom corrugated cardboard of a stack of corrugated cardboards from a hollow platform at the front of the machine by an air extraction device, so that the corrugated cardboards are placed equidistantly with one another on the platform and slightly higher than a plurality of conveyor belts on the surface of the platform, and then transmitting each conveyor belt by a clutch mechanism to rub, drive and send the bottom corrugated cardboard into a transfer roller set in the machine, and then extracting the bottom corrugated cardboard of the stack of corrugated cardboards by the transfer roller set, and finally feeding the corrugated cardboard into the corrugated carton machine to carry out other manufacturing processes such as creasing, slotting, printing, and cutting processes. 
     However, the air extraction device has air extraction passages interconnected with each hollow position of the platform, so that the flow of the air extraction is distributed uncertainly all over the platform due to the size and area of the corrugated cardboard, and idle suctions occur frequently and cause unnecessary waste of energy. In this situation, the air extraction power must be increased. In addition, the extraction force varies with the area and idle suction position of the corrugated cardboard, so that different pressures may be exerted on the corrugated cardboard and its contact surface with each conveyor belt, and uneven wearing may occur. Therefore, the corrugated cardboard bears a conveying force with uneven frictions and results in a skew feed and affects the quality of transferring the corrugated cardboard from the transfer roller set for manufacturing operations at a later stage. 
     In view of the aforementioned problems and drawbacks of the prior art, the inventor based on years of experience in the related industry to conduct extensive researches and experiments, and finally designed and develop a front-edge paper feeding device in accordance with the present invention to provide quick delivery and smooth separation of paper materials and facilitate the operations in a later manufacturing process. 
     SUMMARY OF THE INVENTION 
     Therefore, it is a primary objective of the present invention to provide a front-edge paper feeding device applicable for automatically and quickly conveying stacked cardboards at a front edge of different operating procedures. 
     To achieve the aforementioned and other objectives, the present invention provides a front-edge paper feeding device comprising a plurality of transmission shafts, a grid plate, at least one servomotor, a control element and a suction box, wherein the transmission shaft includes a plurality of conveyor rollers axially installed to the transmission shafts, and the grid plate is covered onto the plurality of transmission shafts and controlled by the control element to elevate and descend reciprocally, and the transmission shaft is rotated intermittently by the servomotor. During operation, the cardboard is placed on the grid plate. When the grid plate elevates, the cardboard is separated from the conveyor wheel, and the control element controls the grid plate to elevate and descend reciprocally. When the grid plate descends, the conveyor wheel is exposed, so that the cardboard is in contact with the conveyor wheel, and the suction box drives the cardboard to fall quickly and attach onto the grid plate, and the servomotor is operated to rotate the transmission shaft while driving the conveyor wheel, so that the conveyor wheel drive the cardboard to move in order to convey and output the cardboard, so as to achieve the effects of feeding paper continuously and smoothly and conveying the cardboard intermittently. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the present invention; 
         FIG. 2  is a schematic view of a partial structure of the present invention; 
         FIG. 3  is a schematic view of linking a grid plate of the present invention; 
         FIG. 4  is a schematic view of operating a grid plate of the present invention; 
         FIG. 5  is a schematic view showing a first status of conveying a cardboard of the present invention; 
         FIG. 6  is a schematic view showing a second status of conveying a cardboard of the present invention; and 
         FIG. 7  is a schematic view of linking a transmission shaft of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will become clearer in light of the following detailed description of an illustrative embodiment of this invention described in connection with the drawings. It is intended that the embodiments and drawings disclosed herein are to be considered illustrative rather than restrictive. 
     With reference to  FIGS. 1 and 2  for a perspective view and a partial structural view of a front-edge paper feeding device of the present invention respectively, the front-edge paper feeding device comprises a plurality of transmission shafts  10 , a grid plate  20 , at least one servomotor  30 , a control element  40  and a suction box  91 . 
     The transmission shafts  10  are arranged parallel to each other, and the transmission shafts  10  are axially installed to a plurality of conveyor rollers  11  respectively. 
     The grid plate  20  is covered onto the plurality of transmission shafts  10 , and the grid plate  20  includes a plurality of broken holes  21  formed at positions corresponsive to the plurality of conveyor rollers  11  respectively. The grid plate  20  is able to elevate and descend between the conveyor rollers  11 . 
     The servomotor  30  is connected to the plurality of transmission shafts  10  for controlling the transmission shafts  10  to rotate intermittently. 
     The control element  40  is connected to the grid plate  20  for controlling the grid plate  20  to elevate and descend reciprocally. 
     The suction box  91  is installed under the transmission shafts. 
     With reference to  FIGS. 3 and 4  for an embodiment of the present invention, an end of the grid plate  20  is connected to the control element  40 , and the other end of the grid  20  is installed with a shaft member  22 , and the axis of the shaft member  22  acts as a fulcrum for rotation. In addition, the control element  40  includes a power shaft  41 , a crank  42  and a link lever  43 , wherein an end of the crank  42  is linked to the power shaft  41 , and the other end of the crank  42  is linked to the link lever  43 , and the power shaft  41  is pivotally connected to an eccentric wheel  44  and provided for driving the crank  42  to elevate and descend reciprocally through the eccentric wheel  44 , and the crank  42  drives the link lever  43  to elevate or descend, and an end of the grid plate  20  is connected and fixed to the shaft member  22  which uses its axis as a fulcrum, and when the other end of the grid plate  20  is driven by the link lever  43 , the grid plate  20  is elevated and descended reciprocally with a curvature. 
     When the present invention is operated on the grid plate  20 , a stack of cardboards to be conveyed can be placed on the grid plate  20 . When the grid plate  20  descends, the conveyor wheel  11  is exposed, so that the cardboard is in contact with the conveyor wheel  11 , and the servomotor  30  is operated to drive the transmission shaft  10  to rotate intermittently, and the transmission shaft  10  synchronously drive the conveyor wheel  11  to rotate, so that the stack of cardboards on the conveyor wheel  11  is rotated with the conveyor wheel  11  accordingly and moved to achieve the effects of conveying and outputting the cardboards one by one, feeding the paper continuously and smoothly, and conveying the cardboards intermittently in cycles. When the grid plate  20  ascends, the grid plate  20  separates the contact between the next cardboard and the conveyor wheel  11 , and the timing for elevating and descending the grid plate  20  is set according to the length of the cardboard and the conveying time interval. If the cardboard is situated at a stationary state, the grid plate  20  will wait till the next time of descending, and the conveyor wheel  11  will be rotated again for conveying the cardboard. 
     With reference to  FIGS. 5 and 6  for another embodiment of the present invention, a baffle  60  is arranged at the grid plate  20  and proximate to a position above an edge of the shaft member  22 , and a stack of cardboards  50  is outputted and the cardboards  50  are conveyed one by one in a direction towards the bottom of the baffle  60 , and the stack of cardboards  50  is placed on the grid plate  20 , so that a first cardboard  51  in the stack of cardboards  50  is in contact with the grid plate  20 , and a second cardboard  52 , a third cardboard  53  . . . are stacked and superimposed with one another on the first cardboard  51 . In addition, the second cardboard  52  and the third cardboard  53  abut the baffle  60 . The transmission shaft  10  is rotated in a direction of outputting the cardboards. When the grid plate  20  descends to a position such that the first cardboard  51  is in contact with the conveyor wheel  11 , the transmission shaft  10  situated at the stationary state starts to rotate, and a maximum static friction produced between the first cardboard  51  and the conveyor wheel  11  drives the first cardboard to pass through the baffle  60  easily and to be outputted successfully (as shown in  FIG. 5 ). In addition, the baffle  60  includes an upper paper feed roller  70  and a lower paper feed roller  80  installed opposite to the other side of the grid plate, and a gap is formed between the upper paper feed roller  70  and the lower paper feed roller  80 , and the first cardboard  51  are engaged by the upper paper feed roller  70  and the lower paper feed roller  80  and conveyed continuously to a work station. 
     When the first cardboard  51  is outputted, the grid plate  20  is descended by using the axis of the shaft member  22  to rotate, so that the second cardboard  52  presses at the grid plate  20  due to the gravitational force of the stack of cardboards  50  and swings in an arc with the grid plate  20  to descend in a direction away from the baffle  60  and slide slantingly, so as to prevent possible deformations occurred at the edge of the second cardboard  52  due to the compression or friction from the baffle  60  and avoid unsmooth conveying. Further, a suction fan  90  is provided for producing suction by the suction box  91  to accelerate the second cardboard  52  to fall down and contact with the grid plate  20 . After the first cardboard  51  is passed through the baffle  60  completely and sent out, the transmission shaft  10  will stop rotating, and a side of the grid plate  20  will be elevated by using the shaft member  22  as an axis, so as to prevent the second cardboard  52  from being in contact with the conveyor wheel  11  or prevent the second cardboard  52  from being sent out accidentally. The time interval or distance interval for conveying the first cardboard  51  and the second cardboard  52  may be controlled. The second cardboard  52  is sent by descending the grid plate  20  through rotation by using the shaft member  22  as the axis of rotation. When the second cardboard  52  is in contact with the conveyor wheel  11 , the transmission shaft  10  situated at the stationary state starts rotating and repeat the cycle of conveying the second cardboard  52  similar to that of the first cardboard  51 . 
     In  FIG. 7 , the servomotor  30  includes a gear set  31 , and the servomotor  30  is linked to the transmission shaft  10  through the gear set  31 , and the gear set  31  may be linked to two transmission shafts  10 , and there may be two servomotors  30  for driving the operation of four transmission shafts  10 . In addition, a regulator (not shown in the figure) is connected to the servomotor  30  and the control element  40  and provided for adjusting the intermittent movement speed of the servomotor  30  and the control element  40 , so that cardboards of different sizes and lengths can be conveyed one by one smoothly within appropriate conveying time intervals. 
     In summation of the description above, the present invention improves over the prior art, and is thus duly filed for patent application. While the invention has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.