Abstract:
It is an object to provide a banding packing machine capable of easily processing a right presser member, a left presser member and a middle presser member, reducing the number of parts and readily carrying out attachment with high precision. A drum portion of at least a middle presser member ( 24 ) provided in a central part in a right presser member ( 22 ), a left presser member ( 23 ) and the middle presser member ( 24 ) has a sectional shape of an almost track including a pair of circular arc portions ( 26   a,    26   d ) opposed to each other and a pair of straight portions ( 26   c,    26   d ) opposed to each other, and one of ends of each of drum portions ( 27, 28 ) in the right presser member ( 22 ) and the left presser member ( 23 ) which are opposed to the straight portions ( 26   c,    26   d ) of the middle presser member ( 24 ) is formed rectilinearly.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of The Invention  
           [0002]    The present invention relates to a banding packing machine and more particularly to a banding packing machine capable of transmitting, with high precision, an operation of a cam mechanism provided to carry out cutting, welding and the like for binding a band.  
           [0003]    2. Description of The Related Art  
           [0004]    In an automatic or semi-automatic banding packing machine, a band led from a band reel is wound upon an object to be packed and is then clamped, and subsequently, is returned to the band feeding side and is tightened. Thereafter, a bound portion is melted by a heater almost simultaneously with the cutting and is bonded by means of a press. The timing of these operations is usually made by means of a cam mechanism.  
           [0005]    [0005]FIG. 11 shows the structure of a control portion for carrying out an operation such as clamp, welding, cutting and the like for a tip portion of a band based on the cam mechanism in a conventional banding packing machine.  
           [0006]    In the control portion, a right presser member  5 , a left presser member  6  and a middle presser member  7  are accommodated in a support block  52  in the vicinity of a face where an object to be packed is to be provided, and are supported on a pair of fixed plates  12  and  13  through a screw member  54  or the like.  
           [0007]    The right presser member  5 , the left presser member  6  and the middle presser member  7  have such a structure that rollers  14 ,  15  and  16  provided on lower ends thereof abut on separate cams fixed to one common cam shaft and a vertical movement is carried out in a predetermined timing according to the cams. The rollers  14 ,  15  and  16  are pulled toward the cam side with springs  17 ,  18  and  19  such that they are maintained in the abutment state on the cams.  
           [0008]    The right presser member  5 , the left presser member  6  and the middle presser member  7  according to the conventional art have been mainly formed cylindrically.  
           [0009]    However, the cylindrical members are high workability and might be slightly rotated in the middle of the vertical movement. In this case, the clamping operation or the cutting operation of a cutter is not stabilized so that the operation and function of the presser member are adversely affected. In order to avoid such a situation, it is preferable that a detent mechanism for controlling a rotation should be provided separately. However, there is a problem in that the number of parts is increased or the mechanism is complicated.  
           [0010]    Moreover, there have been known square-shaped members. In that case, four faces should be polished or corner portions should be perpendicular. Thus, the square shape needs more precise processings than the circular shape.  
         SUMMARY OF THE INVENTION  
         [0011]    In consideration of the above-mentioned circumstances, it is an object of the present invention to provide a banding packing machine in which a right presser member, a left presser member and a middle presser member can be processed easily and the number of parts is decreased, and furthermore, they can be assembled readily with high precision and are not rotated during sliding.  
           [0012]    In order to achieve the above-mentioned object, the present invention provides a banding packing machine in which a tip portion of a band is clamped, is returned from a band feeding side and is tightened and a band superposition portion is melted by a heater. The band feeding side is then cut and bonded in a process of causing a right presser member, a left presser member and a middle presser member arranged rectilinearly opposite to a slide table for freely appearing on a band traveling path constituted on a packing machine body to approach to or separate from each other through an operation of a cam mechanism, wherein a drum portion of at least the middle presser member provided in a central part in the right presser member, the left presser member and the middle presser member has a sectional shape of an almost track including a pair of circular arc portions opposed to each other and a pair of straight portions opposed to each other, and one of ends of each of drum portions in the right presser member and the left presser member which are opposed to the straight portions of the middle presser member is formed rectilinearly.  
           [0013]    According to such a structure, it is sufficient that a processing of simply exposing a flat face from a circular shape is carried out. Therefore, the processing of obtaining precision can be performed comparatively easily and a rotation can be prevented without requiring a detent mechanism. Moreover, a distance between the right presser member and the left presser member can be reduced. Consequently, the size of a corresponding slide table can be reduced. Thus, the present invention can contribute to a reduction in the size of the structure.  
           [0014]    In the banding packing machine according to the present invention, moreover, the drum portions of the right presser member, the left presser member and the middle presser member can also be accommodated in a support block having an integral structure in which three communicating or overlapping holes corresponding to their shapes are provided.  
           [0015]    With such a structure, these three members are guided into the three communicating holes of the support block so that a vertical movement is carried out with a plane contact. Therefore, rotation of the three members is prevented in a reliable manner.  
           [0016]    As described above, according to the banding packing machine of the present invention, the left presser member, the middle presser member and the right presser member are vertically moved while coming in contact with each other on a plane basis. Therefore, they are not rotated. Accordingly, it is possible to transmit, with high precision, the operation of the cam mechanism provided to carry out cutting, welding and the like for binding a band. Moreover, the portions of the presser members other than the planar portions are formed like a circular arc. Therefore, in the case in which the whole body is to be formed, it is sufficient that a circular shape is cut. Therefore, high workability can be obtained.  
           [0017]    Furthermore, if these three members are accommodated in the support block, they are guided vertically while coming in contact with the planes with the outer peripheral side bound through the support block. Therefore, a possibility that the rotation might be carried out can be lessened still more.  
           [0018]    According to the present invention, furthermore, the three members are caused to come in contact with each other on a plane basis. Therefore, it is possible to reduce the assembly width of the whole block including the right presser member, the left presser member and the middle presser member and to reduce a size, and furthermore, to decrease the width of the slide table to abut on the three members.  
           [0019]    These objects as well as other objects, features and advantages of the present invention will become more apparent to those skilled in the art from the following description with reference to the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    [0020]FIG. 1 is an exploded perspective view showing a control portion of a banding packing machine according to an embodiment of the present invention,  
         [0021]    [0021]FIG. 2 is a plan view illustrating the external shapes of drum portions of a left presser member, a middle presser member and a right presser member which constitute the control portion in FIG. 1,  
         [0022]    [0022]FIG. 3 is an exploded perspective view showing the left presser member according to the embodiment,  
         [0023]    [0023]FIG. 4 is an exploded perspective view showing the middle presser member according to the embodiment,  
         [0024]    [0024]FIG. 5 is an exploded perspective view showing the right presser member according to the embodiment,  
         [0025]    [0025]FIG. 6 is a front view showing a cam mechanism according to the embodiment,  
         [0026]    [0026]FIG. 7 is a view illustrating the initial state of the control portion when banding is to be carried out,  
         [0027]    [0027]FIG. 8 is a view illustrating a state in which a band is tightened when the banding is to be carried out,  
         [0028]    [0028]FIG. 9 is a view illustrating a state of welding in which the banding is to be carried out,  
         [0029]    [0029]FIG. 10 is a view illustrating a state of band cutting in which the banding is to be carried out, and  
         [0030]    [0030]FIG. 11 is a view illustrating the structure of a conventional control portion. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0031]    An embodiment of the present invention will be described below with reference to the drawings.  
         [0032]    [0032]FIG. 1 is a view showing the main part of a control portion of a banding packing machine according to the embodiment of the present invention.  
         [0033]    In the present embodiment, a right presser member  22 , a left presser member  23  and a middle presser member  24  are formed such that drum portions  27 ,  28  and  26  thereof have external shapes shown in FIG. 2.  
         [0034]    More specifically, as shown in FIG. 2, the drum portion  26  of the middle presser member  24  provided in a central part has an external shape including a pair of circular arc portions  26   a  and  26   b  opposed to each other and a pair of straight portions  26   c  and  26   d  opposed to each other, and is wholly formed to have an almost track shape.  
         [0035]    On the other hand, the external shape of the drum portion  27  of the right presser member  22  is constituted by a circular arc portion  27   a  and a straight portion  27   b.  The straight portion  27   b  is opposed to the straight portion  26   d  of the middle presser member  24 .  
         [0036]    Moreover, the external shape of the drum portion  28  of the left presser member  23  is constituted by a straight portion  28   a  and a circular arc portion  28   b.  The straight portion  28   a  is opposed to the straight portion  26   c  of the middle presser member  24 .  
         [0037]    The left presser member  23  has a head portion and the drum portion  28  formed integrally. A head portion  29  and the drum portion  27  of the right presser member  22 , and a head portion  30  and the drum portion  26  of the middle presser member  24  which are formed separately are attached integrally, respectively. Moreover, the inner parts of the drum portions  28 ,  26  and  27  have hollow shapes, and a spring  31  is incorporated therein and a plunger  32  is slidably inserted thereunder as shown in FIGS. 3, 4 and  5 . A nick portion  33  is formed on the lower end of the plunger  32 . A roller  36  to abut on a cam mechanism  60  shown in FIG. 6 is rotatably provided in the nick portion  33 .  
         [0038]    A pin hole  34  is formed in the drum portions  28 ,  26  and  27  and an insertion hole  37  is formed on the plunger  32 . In a state in which the plunger  32  is inserted in the drum portions  26 ,  27  and  28 , the pin hole  34  is matched with the insertion hole  37  and a pin  39  is then inserted in the holes  34  and  37  such that the plunger  32  does not slip out of the drum portions  26 ,  27  and  28 . The insertion hole  37  has a diameter which is much larger than the diameter of the pin  39 . Consequently, the spring  31  is extended by a difference between the diameters, thereby functioning as a cushion.  
         [0039]    The three members, that is, the left presser member  23 , the middle presser member  24  and the right presser member  22  according to the present embodiment are formed as described above and are similar to those in the conventional art in that they are supported on a pair of fixed plates  12  and  13  in the same manner as shown in FIG.  
         [0040]    Accordingly, when the roller  36  is moved vertically in a predetermined timing in conformity with a cam of the cam mechanism, the left presser member  23 , the middle presser member  24  and the right presser member  22  are vertically moved while planes thereof slidably contact the planes abutting each other. In this respect, the present embodiment is greatly different from the conventional example.  
         [0041]    In the present embodiment, furthermore, these three members  23 ,  24  and  22  are accommodated in a support block  40  having an integral structure shown in FIG. 1.  
         [0042]    The support block  40  includes three communicating or overlapping holes  41  having sectional shapes corresponding to the shapes of the drum portions  28 ,  26  and  27 . The drum portions  28 ,  26  and  27  are slidably inserted in portions corresponding to the three communicating holes  41 . Accordingly, the left presser member  23 , the middle presser member  24  and the right presser member  22  are vertically moved in the support block  40  while the planes come into contact with each other. Accordingly, the three members cannot rotate during vertical movement imposed by the cam. In such a state that the drum portions  28 ,  26  and  27  are inserted in the support block  40 , the roller  36  attached to the plunger  32  is set to be protruded downward from the three communicating holes  41 . Thus, the roller  36  protruded from the three communicating holes  41  directly abut on cams  56 ,  57  and  58  fixed to a cam shaft  55  of the cam mechanism  60  shown in FIG. 6 such that the rollers  36  do not separate from the respective cams  56 ,  57  and  58 .  
         [0043]    In FIG. 1, the reference numeral  45  denotes a spring holder provided on side surfaces of the presser members  23 ,  24  and  22 . A spring  42  is caught between the spring holder  45  and a shaft  61  on the body side so that the roller  36  reliably comes into contact with the cams  56 ,  57  and  58  and does not separate therefrom. Moreover, the reference numeral  46  denotes a non-slip portion provided in the left presser member  23 . A band B is held by the non-slip portion  46 . The reference numeral  47  denotes a cutting blade provided in the middle presser member  24 . The band B is cut between the cutting blade  47  and the right presser member  22 . The reference numeral  48  denotes a guide hole provided in the right presser member  22  for inserting the band B therethrough, and the reference numeral  49  denotes a non-slip portion provided in the right presser member  22 .  
         [0044]    While the control portion in the banding packing machine according to the present embodiment has the above mentioned structure, the function thereof will be described below. The same elements as those in FIG. 11 have the same reference numerals and description will be given.  
         [0045]    As shown in FIG. 7, a band guide  2  is positioned on the lower surface of a slide table  1 . In this state, the band B is inserted into a guide hole  48  of the right presser member  22  and a guide passage  4  of the band guide  2  by the driving force of a band feeding roller  50 . When the tip of the band B abuts on a stopper  3 , the right presser member  22  is lifted to interpose the band B between the non-slip portion  49  and the slide table  1  as shown in FIG. 8. When the band B is thus interposed completely, the band guide  2  is caused to retreat from a band traveling path.  
         [0046]    After the band guide  2  is caused to retreat from the band traveling path, the band feeding roller  50  is reversed in directions of arrows in FIG. 8 to pull the band B. Consequently, the band B is forcibly removed from a band guide arch  51  and is wound onto an object W to be packed. When the band B is wound onto the object W to be packed, band B is further pulled and tightened. After the band B is thus tightened, the left presser member  23  is moved to an uppermost position to interpose the binding rear end side of the band B between the non-slip portion  46  of the left presser member  23  and the slide table  1  as shown in FIG. 9. In this state, the binding tip portion of the band B and the binding rear end portion are opposed to each other with a space maintained vertically. A heater  53  is inserted in the space as shown in FIG. 9, thereby melting the surface of the band B. When the surface of the band B is molten, the middle presser member  24  is lifted to push the molten portion thereagainst and is bonded thereto as shown by the arrow in FIG. 10. At this time, the cutting blade  47  of the middle presser member  24  cuts the band B together with the right presser member  22 .  
         [0047]    Thus, a series of banding works are carried out based on the operation of the cam mechanism  60  shown in FIG. 6 and the banding on the object W to be packed is ended.  
         [0048]    In the present embodiment, thus, both ends of the middle presser member  24  are formed rectilinearly, that is, on a plane and one of the ends of the left presser member  23  and one of the ends of the right presser member  22  which are opposed to the respective rectilinear end are formed rectilinearly, and the hole of the support block  40  accommodating them is constituted by one continuous hole. Therefore, these three members are vertically moved while the planes thereof come into contact with each other in the hole of the support block  40 . Since the members are thus moved vertically while coming into contact with each other on the planes, they are not rotated on the way of the vertical movement. Consequently, the motion of the cam mechanism  60  through the cam shaft  55  and the cams  56 ,  57  and  58  can be transmitted accurately to the bound portion of the band B. Moreover, it is sufficient that a straight line is formed by working a circle in these processings. Therefore, workability can be enhanced.  
         [0049]    Moreover, the assembly width of the right presser member  22 , the left presser member  23  and the middle presser member  24  can be reduced by virtue of the area of material removed from the presser members in forming the planar guide surfaces. Therefore, the width of the slide table  1  can be reduced.  
         [0050]    While the embodiment of the present invention has been described above, the present invention is not restricted to the above-mentioned embodiment. Although the left presser member  23 , the middle presser member  24  and the right presser member  22  are accommodated in the support block  40  in the above-mentioned embodiment, the support block  40  is not indispensable.  
         [0051]    Moreover, it is a matter of course that the present invention can be applied to both an automatic packing machine and a semi-automatic packing machine.  
         [0052]    Numerous modifications and alternative embodiments of the present invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, this description is to be construed as illustrative only, and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure and/or function may be varied substantially without departing from the spirit of the invention and all modifications which come within the scope of the appended claims are reserved.