Abstract:
A holding assembly for an edge of a flexible film sheeting where the assembly comprises an elongate flexible channel member for extending along the edge and an elongate locking strip detachably engagable within the channel member for clamping the associated film sheeting therebetween has the locking strip moved into place by a guide body arranged for sliding movement across a support surface such as the ground on which the film sheeting is located. The guide body having a slot therein for receiving the channel member and carries a pivotal lever including a pair of rollers for guiding and forcing the locking strip into place. The guide body is carried on a skid and moves underneath the edge of the film across the width of the opening to be closed.

Description:
[0001]    This invention relates to a sliding tool for insertion of a locking strip into a channel for sealing the edge of a film. 
       BACKGROUND OF THE INVENTION 
       [0002]    Devices for sealing the edge of a sheet of plastics film or the like are shown in U.S. Pat. No. 3,505,725 issued Apr. 14, 1970; in U.S. Pat. No. 3,893,212 issued Jul. 8, 1975 and in U.S. Pat. No. 3,999,258 issued Dec. 28, 1976 all by Walter Curry one of the inventors herein. 
         [0003]    In each of these devices there is shown a channel member which has a longitudinal channel extending along a length of the channel member and a locking strip which can be inserted into the channel and engaged under side edges of the channel so that the locking strip is held in place. The locking strip is slightly loose within the channel so that one or more sheets of plastic film can be engaged into the channel and underneath the locking strip so as to be held in place between the locking strip and the channel. 
         [0004]    This arrangement is used in many different circumstances. In one particular end use, the arrangement is used to seal together two overlying sheets of the plastic material so as to form a seam therebetween. This is particularly useful for closing the ends of large bags for example the very tubular bags used for storing silage in the field. However very many other uses are available for an arrangement where two overlying sheets of plastic film are fastened together? 
         [0005]    One difficulty in using the locking system disclosed in the above patents is that of inserting the locking strip into the channel member, particularly when the channel member and the locking strip are relatively large and therefore relatively stiff in order to engage and seal the relatively thick plastics material necessary for large bags. 
         [0006]    U.S. Pat. No. 3,893,212 shows two different arrangements of tool which can be used to insert the locking strip into the channel. In one arrangement the channel is generally symmetrical on each side so that the locking strip is bent inwardly at its edges to tuck into the channel. In an alternative arrangement the channel is stiffer and more containing on one side allowing the locking strip to be inserted into that side following which the other side of the locking strip is tucked under a softer more pliable edge piece of the channel member. 
         [0007]    Typically when using even the larger arrangements of this type, a rolling tool or wheel somewhat similar to that shown in FIGS. 3 and 4 of the above U.S. patent is used to engage the edge of the locking strip to push it into place. This is a hand operated tool which slides along or rolls along the locking strip. In a situation where it is necessary to close a large bag, it is necessary for the user to crawl along the edge of the bag pushing the tool along the locking strip while holding the locking strip in the required position. This is sufficiently difficult that it has led to some resistance to use of a system of this type thus reducing potential sales and thus reducing the possibility for the user to utilize the effective sealing action of a device of this type. 
         [0008]    In some cases therefore, in the field, the ends of such large bags are closed by simple crude mechanisms using wooden strips and the like which are rolled at the edge of the bag. This crude system is sometimes used in replacement for the effective sealing action of the device of the above type in view of the difficulty of the installation. 
         [0009]    It is one object of the present invention, therefore to provide a tool which can be used to more effectively insert the locking strip into the channel member in an arrangement of this type. 
       SUMMARY OF THE INVENTION 
       [0010]    It is one object of the invention to provide a sliding tool for insertion of a locking strip into a channel for sealing the edge of a film. 
         [0011]    According to one aspect of the invention there is provided an apparatus for use with a clamping and holding assembly for an edge of a flexible film sheeting where the assembly comprises an elongate flexible channel member for extending along the edge and an elongate locking strip detachably engagable within said channel member for clamping the associated film sheeting therebetween, the apparatus comprising: 
         [0012]    a guide body arranged for movement across a support surface on which the film sheeting is located; 
         [0013]    the guide body having a slot therein for receiving the channel member; 
         [0014]    the guide body carrying a guide member including a first guide element for guiding the locking strip to the channel member so that one side edge enters an adjacent edge of the channel member and a second guide element for forcing the opposite side edge of the locking strip into the channel member; 
         [0015]    the guide body being movable along the support surface with the channel member in the slot so as to move along the channel member and to guide the locking strip into the channel member as the guide body moves relative to the channel member and the locking strip. 
         [0016]    Preferably the guide body has a bottom skid for sliding across the surface for sliding on soil or other rough surfaces where wheels are ineffective. Alternatively the guide body may include wheels to roll over a smooth surface such as concrete. 
         [0017]    Preferably the skid passes underneath the film sheeting. 
         [0018]    Preferably the guide body includes a flat bottom surface so as to lie flat on the surface. 
         [0019]    Preferably the guide member comprises a lever which is mounted on the guide body for pivotal movement about an axis generally parallel to the surface and transverse to the direction of movement. 
         [0020]    Preferably the lever is mounted on the guide body for pivotal movement about a forward end of the lever. 
         [0021]    Preferably the guide body includes a wall at right angles to the surface on which the lever is mounted for the pivotal movement. 
         [0022]    Preferably the first and second guide elements each comprise a wheel mounted on the guide body for rolling movement along the locking strip. 
         [0023]    Preferably each of the wheels includes a peripheral recess adjacent a center of the wheel for receiving and guiding a center bead on the locking strip. 
         [0024]    Preferably the wheel forming the first guide element includes a first surface on the first side of the recess arranged to guide the first respective side edge of the locking strip into the channel and a second surface on the opposite side of the locking strip which is chamfered away from the channel member to allow the second respective side to remain free of the channel member. 
         [0025]    Preferably the wheel forming the second guide element includes a forcing surface on the side of the recess to force the second respective side of the locking strip into the second side of the channel member. 
         [0026]    Preferably the guide body includes an insert guide surface into which the locking strip enters and by which the locking strip is guided as it moves into engagement with the guide body and the guide members thereon. 
         [0027]    Preferably the receptacle comprises a hook. 
         [0028]    Preferably the guide body includes a receptacle along its length on one side of the slot for receiving an edge of the film sheeting projecting beyond the channel member. 
         [0029]    Preferably the receptacle has a mouth underneath the guide member through which the edge of the film sheeting projects. 
         [0030]    According to a second aspect of the invention there is provided a method for clamping an edge of a flexible film comprising; 
         [0031]    placing the edge across an elongate flexible channel member extending along the edge; 
         [0032]    inserting an elongate locking strip within the channel member for clamping the associated film sheeting therebetween; 
         [0033]    wherein the locking strip is inserted by providing a guide body arranged for movement across a support surface on which the film sheeting is located; 
         [0034]    the guide body having a slot therein for receiving the channel member; 
         [0035]    the guide body carrying a guide member including a first guide element for guiding the locking strip to the channel member so that one side edge enters an adjacent edge of the channel member and a second guide element for forcing the opposite side edge of the locking strip into the channel member; 
         [0036]    and moving the guide body along the support surface with the channel member in the slot so as to move along the channel member and to guide the locking strip into the channel member as the guide body moves relative to the channel member and the locking strip. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0037]    One embodiment of the invention will now be described in conjunction with the accompanying drawings in which: 
           [0038]      FIG. 1  is an isometric view of the tool according to the present invention including the channel member and the locking strip in a position of operation of the tool. 
           [0039]      FIG. 2  is a vertical cross section along the lines  2 - 2  of  FIG. 1 . 
           [0040]      FIG. 3  is an enlarged cross sectional view of a part only of the structure of  FIG. 2  showing the second insertion wheel. 
           [0041]      FIG. 4  is a similar cross sectional view to that of  FIG. 3  showing the first insertion wheel. 
           [0042]      FIG. 5  is a front elevational view of the tool of  FIG. 1 . 
           [0043]      FIG. 6  is a cross sectional view showing the position of the locking strip in the first guide element of the tool. 
           [0044]      FIG. 7  is a top plan view of a bag where the end edges of the bag are sealed using the tool of  FIG. 1 . 
       
    
    
       [0045]    In the drawings like characters of reference indicate corresponding parts in the different figures. 
       DETAILED DESCRIPTION 
       [0046]    In  FIG. 7  is shown a bag  10  with overlying sheets  11  at an edge  12  of the bag to be closed. The bag is closed using the channel member and locking strip of the construction shown in the above patents. The channel  13  has a length so that it extends fully across the width of the sheets  11  from a first end  13 A at one side to a second end  13 B at the other side. The channel is cut to length from an extruded strip supplied in roll form and the length is selected so that it matches the length of the bag to be closed. Similarly, a locking strip portion  14  is arranged of a common length with the channel member so that the locking strip can be inserted into the channel member thus pinching the two overlying sheets of the bag together adjacent the edge  12 . The channel member and the locking strip are spaced slightly inwardly from the edge  12  so that a portion of the edge hangs outwardly beyond the channel member to ensure that the channel member receives and contains a complete portion of the two strips and acts to pinch the two strips between the channel member and the locking strip at both side edges of the locking strip to ensure that it is properly held in place. 
         [0047]    In general, in the arrangement shown in  FIG. 7 , the channel member is located underneath the sheets to be joined adjacent the edge  12  and a joining tool generally indicated at  15  is engaged with the channel member. The tool is located underneath the channel member and underneath the sheets and the locking strip is applied from above and inserted by the tool into the channel member. The tool  15  has a length of the order of 12 inches so that it can work on the locking strip over a short portion of locking strip so as to insert that portion of the locking strip into the channel member. The insertion tool  15  can then be pulled across underneath the sheets  11  by a pull cable  16  at one side. Alternatively the tool can be pushed from the other side by an attached push rod, particularly in a situation where the tool needs to be more accurately guided or where there is a tendency to wander from a required straight line. 
         [0048]    It is of course necessary to locate the channel member in the required position so that it is held stationary and prevented from movement as the pulling action occurs. This can be done by attaching the channel member to a suitable locating element such as a wooden component or to the ground itself so that the channel member is fixed in place with the sheets allowing the tool to be pulled along the channel member. Some attention is necessary also to take into account the tendency of the channel member to twist as it is generally unwound from a roll of the material and therefore has a tendency to take a big curvature when laid on the ground. 
         [0049]    It will be appreciated that the discussion herein is directed primarily to the sealing of large bags in an agricultural situation so that the components are placed on the ground but of course the use of the tool herein in other locations is possible where the underlying surface is different and the dimensions involved may also be significantly different both larger and smaller but in relation to the tool itself and in relation to the channel member and locking strip. 
         [0050]    Turning now to the tool itself shown best in  FIGS. 1 ,  2  and  5 , the tool comprises a guide body  20  which has a bottom skid plate  21  for sliding over the surface or the ground. Additional components, such as guide wheels to assist in the sliding action may be provided in accordance with the knowledge of the person well skilled in this art. 
         [0051]    The body provides a slot  22  for receiving the channel member defined by a pair of upstanding walls  23  and  24 . The slot has a width sufficient to receive the channel member with side to side freedom to move. The sheets  11  can be laid over the top of the side walls  23  and  24  and across the top of the channel member  13  within the slot. The guide body further includes a further upstanding wall  25  parallel to the walls  23  and  24  and spaced behind the wall  23 . At the top of the wall  25  which rises to the height above the top of the walls  23  and  24  is provided a horizontal top plate  26  which attaches to a depending wall  27  extending downwardly from a top plate  26  to a position closely adjacent the top of the upstanding wall  23 . The walls  25 ,  26  and  27  thus define a receptacle  28  with a hollow interior and also define a slot  29  between the bottom edge  27 A of the depending wall  27  and the top edge  23 A of the wall  23 . The hollow receptacle  28  can readily receive and contain the edge portion of the sheets  11  adjacent the edge  12 . 
         [0052]    The tool  20  provides the above components in an arrangement longitudinal and can be manufactured for example as an extrusion so that the walls defined are continuous along the length of the structure. 
         [0053]    On the depending wall  27  is provided a lever  31 . As best shown in  FIG. 1 , this is mounted on a pivot pin  32  at the forward end of the lever adjacent one end of the tool. The pin  32  attaches the lever to the wall  27  and thus defines a pivot axis which is at right angles to the tool and parallel to the ground. 
         [0054]    The lever  31  carries three components for guiding and directing the locking strip  14 . The first component  33  forms a hook as best shown in  FIG. 6  where the hook defines a channel shape receptacle  34  between two legs  35  and  36  connected by a U-shaped base  37 . This channel shape receptacle formed in the hook thus receives and guides the locking strip  14  so that it is properly oriented as it moves toward the forward end of the tool in the locking action. 
         [0055]    The lever  31  can be lifted by pivoting about the pin  32  to allow the strip to be threaded into position and then lowered to commence the pressing and insertion action. In the lowered position, there is a latch  30  holding the lever in place so that it remains lowered as the tool is moved. 
         [0056]    The second component of the locking system as best shown in  FIG. 4  provides a roller wheel  38  which acts to provide initial guidance of the locking strip so as to insert the locking strip into the channel member. 
         [0057]    As explained in the previous patents, the channel member includes two side edges  13 C and  13 D. The side edge  13 C forms a receptacle portion  13 E into which the side edge  14 A of the locking strip can be inserted. This side of the channel member is relatively stiff and is not intended to be flexed during the insertion of the locking strip. Thus the edge  14 A of the locking strip is inserted firstly under the lip defined by the side  13 C so that edge slides underneath that lip and engages the strips of material forcing the strips toward that end of the channel member. 
         [0058]    In order to effect this movement, the wheel  38  includes a central peripheral recess  38 A which receives a bead  14 B on the top of the locking strip at a position adjacent the center of the locking strip. Thus the locking strip is received on the guide wheel and is located side to side by the engagement of the bead  14 B into the recess  38 A. On the side of the wheel  38 A adjacent the side  13 C of the channel member is provided a rib  38 B which engages the portion of the locking strip adjacent the side  13 C and acts to insert that side of locking strip into its position underneath the side  13 C at that lip. On the other side of the recess  38 A is provided a rib  38 C which has a chamfered surface  38 D recessed away from the channel member so as to form a nose portion  38 E which engages the locking strip and a side  38 D which extends outwardly toward the side  13 D and radially inwardly toward the wheel. Thus the side  14 C of the locking strip is allowed to remain out of the channel member during the engagement with the wheel  38 . In this way the locking strip is guided so that it enters under the side  13 C but remains outside the side  13 D. 
         [0059]    Turning now to  FIG. 3 , the final guide element is indicated at  40  and comprises a further wheel similarly shaped to the guide wheel  38 . Thus the guide wheel includes a recess  40 A and two ribs  40 B and  40 C. 
         [0060]    Both of the wheels are mounted on the lever for rotation around an axle  31 A and  31 B on the lever. However the guide wheels are held in position fixed relative to the side wall  27  during the insertion action. 
         [0061]    The lever  31  is pivotal relative to the side wall  27  in an initial setting position so as to fit the guide elements  33 ,  38  and  40  out of engagement with the locking strip for ready insertion of the lead end of the locking strip into the channel member. However after this insertion is completed, the lever  31  is moved downwardly and locked in place so that the hook guide  33  remains in position adjacent the channel member and the wheels  38  and  40  are located at the required position so their peripheral surfaces engage the locking strip and force it into the positions shown in  FIGS. 3 and 4 . 
         [0062]    The wheel  40  as shown in  FIG. 3  has a rib  40 C similarly positioned to the rib  38 C but in this case the rib  40 C is not chamfered but instead provides a cylindrical outer surface  40 D which engages the top surface of the locking strip at the side  13 D and pushes it downwardly past the flexing side lip  13 D into the channel member. 
         [0063]    Thus the three guide elements act to accurately guide and direct the locking strip to the required location and then to force the locking strip into the channel member as the channel member passes along the slot caused by the movement of the tool across the width of the bag and along the channel member. 
         [0064]    In this way the tool can be simply placed into its required location under the edge of the bag and the tool can be rapidly pulled across the bag to effect the sealing action. 
         [0065]    Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.