Abstract:
An automatic carton slitting machines includes a transmission means for moving cartons, a sensing and positioning means for detecting and positioning the cartons at locations desired, a slitting means for slitting the carton and a control unit for coordinate and control the operations of all other means. The cutter means includes two spaced cutter sets each has a motor driven rotating saw cutter with adjustable slitting angle. One of the cutter sets is movable by a cutter set moving means for changing spacing distance between the cutter sets to process carton of different width. The cutter means also has a frame lifting means to adjust cutter sets height for processing cartons of different height. Through coordinating the transmission means, cutter set moving means and frame lifting means may coordinate their motion so that the cutter sets may move in three dimensions against the carton for automatically cleaving cartons of different size.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to an automatic carton slitting machine and particularly to an automatic carton slitting machine for slitting upper lid of carton of different sizes.  
           [0003]    2. Description of the Prior Art  
           [0004]    For mass merchandisers, chain stores, big wholesalers, large distributors and the like, there is a need for processing huge amount of goods containing in cartons of various sizes. It takes a great deal of manpower to slit and open the cartons to take out the goods for display or sales. Traditionally this carton handling work is done by people using a knife to slit open the four lateral sides of the carton top lid. It is a labor intensive and time consuming job. Moreover people may get hurt by knife accidentally and results in a drop of work efficiency.  
           [0005]    There is a semiautomatic carton slitting machinery being developed for improving the carton slitting operation set forth above. It usually needs operators to press buttons to perform the required operations. Moreover one machine usually can handle only one size of carton. There is still a lot of room for improvement regard its work efficiency and flexibility.  
         SUMMARY OF THE INVENTION  
         [0006]    In view of aforesaid disadvantages, it is therefore an object of this invention to provide an automatic carton slitting machine that is able to slit automatically the top lids of cartons of different sizes for achieving higher efficiency, greater flexibility and improved safety for workers.  
           [0007]    It is another object of this invention to provide an automatic carton slitting machine that may slit two lateral sides of cartons. When aligning two such machines in series and normal to each other all four lateral sides of the top lids may be cut open automatically at high speed with consistent quality.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    The invention, as well as its many advantages, may be further understood by the following detailed description and drawings in which:  
         [0009]    [0009]FIG. 1 is a front view of this invention.  
         [0010]    [0010]FIG. 2 is a side view of this invention.  
         [0011]    [0011]FIG. 3 is a top view of this invention.  
         [0012]    [0012]FIG. 4 is a schematic top view of two sets of this invention arranged in series and normal to each other.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0013]    Referring to FIGS. 1, 2 and  3 , a preferred embodiment of this invention includes a transmission means  10 , a sensing and positioning means, a slitting means  30  and a control unit  40  which wires to aforesaid means and controls and coordinates the interaction among various means for automatic operation. The transmission means  10  includes a conveyor  11  which consists of a plurality of roller bars  114  each has a sprocket  115  (or an idler) at one end engaging with a chain (or belt) and driven by a motor  12 . Therefore the roller bars  114  may be turned at same direction simultaneously for moving cartons placed upon the conveyor  11  in a first direction (i.e. longitudinal). The conveyor  11  may be divided separately in a waiting zone  111 , a slitting zone  112  and a discharging zone  113 .  
         [0014]    The sensing and positioning means includes a plurality of sensors  21 ,  22 ,  23  and stoppers  25 ,  26 ,  27  spacely located in the transmission means  10 . The sensors may detect the moving positions of the cartons and then trigger the first stopper  25  to hold a first carton at the waiting zone  111 , the second stopper  26  to hold a second carton at the slitting zone  112  and the third stopper  27  to hold a third carton at the discharging zone  113 . Each of the stoppers  25 ,  26  and  27  is formed like a plank and located between two roller bars  114 , and may be moved above the roller bars  114  by means of a motor, a solenoid valve, a hydraulic cylinder, an air cylinder or the like for stopping a carton from moving forward, and may also be moved below the roller bars  114  to enable the carton moving forward.  
         [0015]    The sensors  21 ,  22  and  23  may be photo sensors or mechanical microswitches. The first sensor  21  aims for detecting if the first carton being properly located in the waiting zone  111 . The second sensor  22  aims for detecting if the second carton being properly located in the slitting zone  112  for slitting operation. The third sensor  23  aims for detecting if the third carton being properly located in the discharging zone  113 . A four sensor  24  may be added at the end of the discharging zone  113  to detect if the processed carton has been moved out of the discharging zone  113 .  
         [0016]    In the slitting zone  112 , there may further be provided with a plural number of width guide posts  28  along a lateral side of the slitting zone for guiding the cartons moving in the correct direction without skewing sideward. The width guide posts  28  are engaged with the second stopper  26  by means of a cam means or the like so that when the second stopper  26  is moved downward for starting slitting operation, the width guide posts  28  will also be moved downward for the carton be moved to a first cutter set  31 .  
         [0017]    The slitting means  30  is located in the slitting zone  112 . It includes the first cutter set  31 , a second cutter set  32 , a cutter set moving means  33 , a frame lifting means  34  and a stand  35  for supporting all the other means of the slitting means  30  set forth above.  
         [0018]    The first cutter set  31  is stationarily mounted on a cutter rack  36 . The cutter set moving means  33  may move the second cutter set  32  in a second direction (i.e., transversely) relative to the first direction so that the distance between the first cutter set  31  and the second cutter set  32  may be changed to suit different width of carton. The first and second cutter sets  31  and  32  have respectively a rotating cutter saws  312  and  322  driven by motors  311  and  321 . The cutting angle of the cutter sets  31  and  32  may be automatically or manually adjusted such as from 90 degrees (normal slitting) to 45 degrees or 60 degrees or other angles desired. The cutter sets  31 ,  32  and the cutter set moving means  33  are mounted on the cutter rack  36  which is movable in a third direction (i.e. up or down) against the first and second directions by means of the frame lifting means  34 . The cutter rack  36  and the frame lifting means  34  in turn are mounted on a stand  35  which is fixedly located above the slitting zone  112 .  
         [0019]    By means of the transmission means  10 , cutter set moving means  33  and frame lifting means  34 , the cutter sets  31  and  32  may perform three dimensional slitting operation on a carton of different sizes. The cutter set moving means  33  includes a guide means  331  (preferably a screw shaft) located in the second direction and a motor  332 . The first cutter set  31  is located at one end of the guide means  331 . The second cutter set  32  is also mounted on the guide means  331  but is spaced from the first cutter set  31 . When the motor  332  is activated, the second cutter set  32  will be driven to move close to or away from the first cutter set  31 . The cutter sets  31  and  32  further engage respectively with a first auxiliary conveyor  313  and a second auxiliary conveyor  323  located thereunder. The auxiliary conveyors  313  and  323  hold and clamp the carton securely when the cutters sets  31  and  32  perform slitting operation on the carton at two lateral sides of the upper lids. The slitting means  30  also may include a plurality of sensors (e.g., microswitches or photo sensors) for measuring relative position of the cutter sets  31  and  32  against the carton so that when the slitting operation is completed, the cutter sets  31  and  32  will be moved back to their initial positions.  
         [0020]    There are also two sensors  333  and  334  fixedly mounted respectively at two ends of the cutter set moving means  33  for defining the leftest and rightest position limit of the second cutter set  32  and thus define the smallest and largest carton width this invention is able to process. The sensor  334  which defines the largest width may be selected as the initial position for the second cutter set  32 .  
         [0021]    On the frame lifting means  34 , there also may be provided with a pair of sensors  341  and  342  vertically spaced from each other for defining the highest and lowest height of the carton. The sensor  341  which defines the highest dimension of the carton may be selected as an initial position for the cutter rack  36 .  
         [0022]    At a lateral side adjacent the first cutter set  31 , a pivotal counter balance weight suspending beam switch  37  is provided which has a low end positioned at a height equal to the slitting height of the first cutter set  31 . When the frame lifting means  34  moves the cutter rack  36  downward, the lower end of the counter balance weight suspending beam switch  37  will touch the top lid of the carton and generate signals to indicate that the top lid of the carton is reached. The control unit  40  will pick up the signals and informs the cutter sets  31  and  32  to ready slitting operation. The counter balance weight suspending beam switch  37  may also press the top lid of the carton so that the carton may be held securely to smooth slitting operation.  
         [0023]    The first cutter set  31  may also provided with a touch sensitive sensor  315 . When the cutter set moving means  33  moves the second cutter set  32  which in turn moves the carton toward the first cutter set  31 , a side wall of the carton will touch the touch sensitive sensor  315 . A signal will be generated and transmitted to the control unit  40  to indicate that the carton is ready for slitting operation. The first and second cutter sets  31  and  32  then will be actuated to start slitting operation.  
         [0024]    In the first and second cutter sets  31  and  32 , there also may be provided with a plural number of sensors for alerting or stopping slitting operation when the carton exceeds the maximum width or height limit allowed. For instance, a high limit sensor  314  may be provided in front of the first cutter set  31  at one end of the waiting zone  111  and is located slightly above the pivotal end of the counter weight suspending beam switch  37 . When a carton moves from the waiting zone  111  to the slitting zone  112  and touches the high limit sensor  314 , the control unit  40  will sound an alert signal or stop the slitting operation automatically. Similarly, a width limit sensor  324  may be provided in front of the second cutter set  32  for alerting if the width of the carton exceeds allowable limit.  
         [0025]    The operating procedures of this invention may follow the steps set forth below:  
         [0026]    1. The first sensor  21  detects there is a first carton being stopped by the first stopper  25  at the waiting zone  111  and generate a signal. The control unit  40  pickups the signal to start the slitting process. The first stopper  25  is moved downward to enable the first carton moving to the slitting zone  112 . The width guide posts  28  keeps the first carton at the proper position of the conveyor  11  without skewing sideward. The first and second cutter sets  31  and  32  are at the initial positions.  
         [0027]    2. The conveyer  11  to the first carton to the slitting zone  112  and is stopper by the second stopper  26  and detected by the second sensor  25 . A signal is generated and sent to the control unit  40  which issues instructions to move the first stopper  25  up again for receiving a next carton to the waiting zone  111 . The cutter set moving means  33  and the frame lifting means  34  move respectively the first and second cutter sets  31  and  32  downward and inward slitting to approach the top lid of the first carton located in the slitting zone  112  in front of the second stopper  26 .  
         [0028]    3. The sensors in the slitting means  30  detect the cutter sets  31  and  32  moving to a predetermined slitting position and trigger the cutter sets  31  and  32  to rotate. The second stopper  26  and the width guide posts  28  are moved downward. The transmission means  10  and the auxiliary conveyors  313  and  323  move the first carton forcefully toward the discharging zone  113  and the two lateral sides of the top lid of the first carton are slitting by the cutter sets  31  and  32  simultaneously.  
         [0029]    4. The slitted first carton is moved into the discharging zone  113  and stopped by the third stopper  27 . The third sensor  23  detects the arrival of the first carton and generates signals to the control unit  40  which then stops the slitting rotation of the cutter sets  31  and  32 .  
         [0030]    The second stopper  26  is moved up again to start the slitting process for the next coming carton. The third stopper  27  is moved downward for the silted carton be moved away from the discharging zone  113  for exit or for another slitting operation on another two lateral sides of the first carton.  
         [0031]    For slitting more than one carton of different size, the cutter sets  31  and  32  will be moved to the initial positions after each slitting operation cycle. For slitting cartons of same size, the cutter sets  31  and  32  will be moved away sightly (such as 15-30 cm) from the slitting position after a carton has been finished but do not return their initial positions for speeding up slitting operation.  
         [0032]    The first cutter set  31  and second cutter set  32  can slit two opposite lateral sides of the carton at one pass. If four lateral sides of the carton need to be silted open, the carton may be turned manually for 90 degrees after the first two lateral sides have been silted open and then be fed to another slitting machine of this invention for process the second two opposite lateral sides. Another way is to use two sets of this invention layed out as shown in FIG. 4.  
         [0033]    Two slitting machines  1   a  and  1   b  are functionally linked in series and normal to each other. At the discharging zone  113   a  of the slitting machine  1   a . There is a mechanical push bar  50  actuated by the control unit  40  to push the carton processed by the slitting machine la to the waiting zone  111   b  of the slitting machine  1   b  for slitting another two lateral sides not yet being silted open. Thus the carton may be processed automatically for all four lateral sides without human intervention.  
         [0034]    It may thus be seen that the objects of the present invention set forth herein, as well as those made apparent from the foregoing description, are efficiency attained. While the preferred embodiments of the invention have been set forth for purpose of disclosure, modifications of the disclosed embodiment of the invention as well as other embodiments thereof may occur to those skilled in the art.  
         [0035]    For instance, the cutter set moving means  33  and the frame lifting means  34  may be driven by various means known in the art such as screw bar, chain, gear, sprocket, belt, steel wire, gear rack and the like. The means for guiding motion direction of the cutter set moving means  33  and the frame lifting means  34  may be a guide screw bar, a sliding bar, a groove channel, a guide rail and the like. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.