Abstract:
A lead edge feeder wheel used in a carton making machine, having a tread for friction contact with a cardboard during rotation to feed the cardboard into the carton making machine cycle by cycle in conjunction with the operation of wheel grids and a vacuum system, and one or multiple grooves extending along the tread for rendering a visual indication when the tread is worn off, avoiding biasing of the cardboard during feeding.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to carton making machine technology and more particularly, to a lead edge feeder wheel for carton making machine that has grooves on the tread thereof that render a visual indication to remind the operator to replace the lead edge feeder wheel when it is worn off. 
         [0003]    2. Description of the Related Art 
         [0004]    A regular carton making machine  10 , as shown in  FIG. 1 , generally comprises a feeding unit  20 , at least one printing unit  30 , a slotting unit  40  and a die cutting unit  50  for carton paper feeding, printing, slotting and creasing, and die-cutting operations respectively. Further, two or more printing units may be used for two-color or multicolor printing (one printing unit can only print one single color). The carton making machine  10  shown in  FIG. 1  uses two printing units  30  and  30   a.    
         [0005]    Subject to the operation of the three rows of feeder wheels  21  and wheel grids  22  (see  FIG. 2 ) of the feeding unit  20  in conjunction with a vacuum system, cardboard  60  is fed into the carton making machine  10 . The conveyer system (not shown) is an enclosed greasing system in which all gearwheels, cams, wheel grid lifting mechanism and interrupter mechanism are enclosed, and the speed of the feeder wheels  21  is controlled subject to vertical movement of the wheel grids  22 . 
         [0006]    As shown in  FIG. 2  and  FIG. 3 , the feeder wheels  21  are elastic, capable of producing a high coefficient of friction with the cardboard  60 . When the machine runs idle (interruption period), the wheel grids  22  are kept in a high position, avoiding direct contact between the cardboard  60  and the feeder wheels  21 . When starting the feeding cycle, the wheel grids  22  are lowered from the high position in supporting the cardboard  60  to a low position below the elevation of the topmost edge of each feeder wheel  21 , allowing direct contact between the cardboard  60  and the feeder wheels  21 . At the beginning of the feeding cycle, the speed of the feeder wheels  21  is almost zero, however, the feeder wheels  21  can be accelerated rapidly to the 100% of the cutting speed of the machine and then kept in this speed during the whole feeding cycle to deliver the cardboard  60  to the first printing unit  30  in between an upper sheet-transfer wheel  31  and a lower impression wheel  32  that in turn transfer the cardboard  60  into the gap between an upper printing wheel  33  and a lower printing wheel  34  for printing a first color of a predetermined pattern. Thereafter, an upper sheet-transfer wheel  31   a  and a lower impression wheel  32   a  of the second printing unit  30   a  transfer the primarily printed cardboard  60  into the gap between an upper printing wheel  33   a  and a lower printing wheel  34   a  for printing a second color of the predetermined pattern. Thereafter, the cardboard  60  is transferred to the slotting unit  40  where the cardboard  60  is creased by an upper creaser wheel  41  and a lower creaser wheel  42  and slotted by an upper slotting wheel  43  and a lower slotting wheel  44 . Thereafter, the cardboard  60  is transferred to the die cutting unit  50  and cut by an upper die-cutting wheel  51  and a lower die-cutting wheel  52  to remove the unnecessary part. Thereafter, the cardboard  60  is folded up into a predetermined shape through a folding unit (not shown) and properly glued by a gluing unit (not shown), and thus the desired carbon is obtained. 
         [0007]    As the feeder wheels  21  and the cardboard  60  is kept in contact with each other under a high coefficient of friction, the feeder wheels  21  wear quickly with use. The allowable limit of wear of the feeder wheels  21  is about 1 mm. If the feeder wheels  21  are excessively worn, the following problems will occur: 
         [0008]    1. When the outer diameter of the feeder wheels  21  become short due to heavy wear, the feeding speed become slow, resulting in inaccurate printing and affecting further slotting and creasing, and die cutting works. 
         [0009]    2. After a long use in feeding small size cardboards to cause wearing of the middle feeder wheels, the lateral feeder wheels may remain intact. When the fabrication is changed to make large size cartons, the cardboard may be biased during feeding due to different friction resistance between the middle feeder wheels and the lateral feeder wheels, affecting further slotting and creasing, and die-cutting works. 
         [0010]    As conventional lead edge feeder wheels for carton making machine do not provide any simple and effective warning design to remind the operator to get a replacement timely. Therefore, users may replace the feeder wheels after 4-6 months in service, or may measure the outer diameter of the feeder wheels to check their wearing status. When the outer meter of one feeder wheel becomes shorter than a predetermined value, the feeder wheel is replaced immediately. However, because the machine is not constantly in operation, a feeder wheel may be replaced too early or too late. If to replace feeder wheels subject to their diameter change, the user must frequently measure the outer diameter of the feeder wheels, preventing unaware overwear. Thus, fairly speaking, both the aforesaid method methods are not simple and effective scientific methods. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a lead edge feeder wheel for carton making machine, which gives a visual warning signal to remind the operator to replace the lead edge feeder wheel when the tread of the lead edge feeder wheel is worn off, assuring accurate cardboard feeding. 
         [0012]    To achieve this and other objects of the present invention, a lead edge feeder wheel comprises a tread for friction contact with a cardboard during rotation to feed the cardboard into the carton making machine, and at least one groove extending along the tread that renders a visual indication when the tread is worn off. 
         [0013]    In one embodiment of the present invention, the lead edge feeder wheel further comprises an annular wheel body having an outer periphery forming the tread and an inner periphery opposing the outer periphery, a mounting hole surrounded by the annular wheel body, and a flange extending along the inner periphery of the annular wheel body and radially projecting into the mounting hole. 
         [0014]    Further, a plurality of protruding portions are spaced around the inner periphery of the annular wheel body within the mounting hole and respectively perpendicularly extending across the flange. The protruding portions have a thickness greater than the flange. One protruding portion is splitted in the middle to facilitate splitting of the lead edge feeder wheel. 
         [0015]    In another embodiment of the present invention, the lead edge feeder wheel further comprises an annular wheel body having an outer periphery forming the tread and an inner periphery opposing the outer periphery, a mounting hole surrounded by the annular wheel body, two beads respectively radially extending along two inner liners of the annular wheel body, and a plurality of protruding portions spaced around the inner periphery of the annular wheel body within the mounting hole and respectively connected between the two beads. One protruding portion is splitted in the middle to facilitate splitting of the lead edge feeder wheel. 
         [0016]    In still another embodiment of the present invention, the lead edge feeder wheel further comprises an arched wheel body having an outer periphery forming the tread and an inner periphery opposing the outer periphery and defining a semi mounting hole, and two wings respectively extended from two distal ends of the arched wheel body in direction toward each other. 
         [0017]    The invention has the advantages as follows: 
         [0018]    When the groove is worn off after a long use of the lead edge feeder wheel, it gives a visual warning signal to the operator, reminding the operator to replace the worn out lead edge feeder wheel timely so that the lead edge feeder wheel can feed a cardboard accurately, avoiding biasing of the cardboard during feeding or any further processing trouble. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    Other and further benefits, advantages and features of the present invention will be fully understood by reference to the following specification in conjunction with the accompanying drawings, in which: 
           [0020]      FIG. 1  is a plain view of a conventional carton making machine. 
           [0021]      FIG. 2  is an elevational view in an enlarged scale of a part of  FIG. 1 , illustrating the arrangement of the feeding unit. 
           [0022]      FIG. 3  is a schematic drawing illustrating a cardboard feeding status of the lead edge feeder wheel of the conventional carton making machine. 
           [0023]      FIG. 4  is an oblique elevation of a lead edge feeder wheel for carton making machine in accordance with a first embodiment of the present invention. 
           [0024]      FIG. 5  is a sectional applied view of the first embodiment of the present invention, illustrating the lead edge feeder wheel attached to a mating wheel rim. 
           [0025]      FIG. 6  is an oblique elevation of a lead edge feeder wheel for carton making machine in accordance with a second embodiment of the present invention. 
           [0026]      FIG. 7  is a sectional applied view of the second embodiment of the present invention, illustrating the lead edge feeder wheel attached to a mating wheel rim. 
           [0027]      FIG. 8  is an oblique elevation of a lead edge feeder wheel for carton making machine in accordance with a third embodiment of the present invention. 
           [0028]      FIG. 9  is a sectional applied view of the third embodiment of the present invention, illustrating the lead edge feeder wheel attached to a mating wheel rim. 
           [0029]      FIG. 10  is an oblique elevation of a lead edge feeder wheel for carton making machine in accordance with a fourth embodiment of the present invention. 
           [0030]      FIG. 11  is a sectional applied view of the fourth embodiment of the present invention, illustrating the lead edge feeder wheel attached to a mating wheel rim. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0031]      FIG. 4  is an oblique elevation of a lead edge feeder wheel  70  for carton making machine in accordance with a first embodiment of the present invention.  FIG. 5  illustrates the lead edge feeder wheel  70  attached to a mating metal wheel rim  80 . The lead edge feeder wheel  70  is a one-piece elastic wheel made of a synthetic resin having a high coefficient of friction, such as urethane, polyurethane (PU) or the like. In this embodiment, the lead edge feeder wheel  70  comprises an annular wheel body  71  having a tread (outer periphery)  72  for friction contact with the workpiece (cardboard), and a mounting hole  73  surrounded by the inner periphery of the annular wheel body  71  for enabling the lead edge feeder wheel  70  to be mounted on the metal wheel rim  80 . The lead edge feeder wheel  70  further comprises an inside flange  74  protruded from and extending along the inner periphery of the annular wheel body  71  and radially projecting into the mounting hole  73  for engaging into a locating groove  81  around the periphery of the metal wheel rim  80 . Thus, the lead edge feeder wheel  70  is secured to the wheel rim  80  for synchronous rotation. As the wheel rim  80  is of the know art, no further detailed description in this regard is necessary. 
         [0032]    The main feature of the present invention is outlined hereinafter. The lead edge feeder wheel  70  further comprises at least one groove  75  extending around the tread  72 . When the groove  75  is worn off after a long use of the lead edge feeder wheel  70 , it gives a visual warning signal to the operator, reminding the operator to replace the worn out feeder wheel timely so that the lead edge feeder wheel  70  can feed a cardboard accurately, avoiding biasing of the cardboard during feeding or any further processing trouble. 
         [0033]    It is to be noted that the depth of the groove  75  is the maximum allowable limit of wear of the lead edge feeder wheel  70 , normally about 1 mm. 
         [0034]    When the groove  75  is worn off or become shadowed, it means the lead edge feeder wheel  70  must be replaced, otherwise the cardboard feeding speed will become excessively slow and the follow-up printing will be inaccurate, affecting further slotting creasing and die-cutting works. 
         [0035]    Further, the structure of the lead edge feeder wheel may vary with the operating system used. The aforesaid lead edge feeder wheel  70  is configured for use in Sun Extend-O-Feed system. The lead edge feeder wheel  70   a  shown in  FIG. 6  is configured for use in Snap-On system.  FIG. 7  illustrates the lead edge feeder wheel  70   a  mounted on a mating wheel rim  80   a . The lead edge feeder wheel  70   b  shown in  FIG. 8  is configured for use in Prime Shur-Feed system.  FIG. 9  illustrates the lead edge feeder wheel  70   b  mounted on a mating wheel rim  80   b . The lead edge feeder wheel  70   c  shown in  FIG. 10  is configured for use in Langston/Staley Rotofeed system.  FIG. 11  illustrates the lead edge feeder wheel  70   c  mounted on a mating wheel rim  80   c.    
         [0036]    In the above description, a lead edge feeder wheel  70  for Sun Extend-O-Feed system is described in detail for easy understanding of the spirit and scope of the present invention. However, this is not a limitation. Other designs of lead edge feeder wheels  70   a ,  70   b  and  70   c  for use in different systems can be configured to provide grooves  75   a ,  75   b  or  75   c  for use as a visual warning mark for replacement when the lead edge feeder wheel  70   a ,  70   b  or  70   c  is worn off. 
         [0037]    Further, the lead edge feeder wheels for different systems are structurally different. The lead edge feeder wheel  70   a  for Snap-On system, as shown in  FIGS. 6 and 7 , comprises an annular wheel body  71   a , a flange  74   a  extending around the inner periphery of the annular wheel body  71   a  and radially projecting into the mounting hole  73   a  that is surrounded by the annular wheel body  71   a , and a plurality of protruding portions  76   a  spaced around the inner periphery of the annular wheel body  71   a  within the mounting hole  73   a  and respectively perpendicularly extending across the flange  74   a . The protruding portions  76   a  have a thickness greater than the flange  74   a . One protruding portion  76   a  is splitted in the middle so that the lead edge feeder wheel  70   a  can be splitted from the split  79   a  of the protruding portion  76   a.    
         [0038]    The lead edge feeder wheel  70   b  for Prime Shur-Feed system, as shown in  FIGS. 8 and 9 , comprises an annular wheel body  71   b , two beads  77   b  respectively radially extending along the two inner liners of the annular wheel body  71   b , and a plurality of protruding portions  76   b  spaced around the inner periphery of the annular wheel body  71   b  within the mounting hole  73   b  that is surrounded by the annular wheel body  71   b  and respectively connected between the two beads  77   b . One protruding portion  76   b  is splitted in the middle so that the lead edge feeder wheel  70   b  can be splitted from the split  79   b  of the protruding portion  76   b.    
         [0039]    The lead edge feeder wheel  70   c  for Langston/Staley Rotofeed system, as shown in  FIGS. 10 and 11 , comprises an arched wheel body  71   c  defining a substantially semicircular mounting hole  73   c , two wings  78   c  respectively extended from the two distal ends of the arched wheel body  71   c  in direction toward each other for securing to the bottom edge of a semicircular wheel rim  80   c  to prevent loosing. 
         [0040]    Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.