Abstract:
The invention is directed to changing the height of the wrapping bar on a lap seal machine so that articles of different heights can be accommodated by making the height of the wrapping bar adjustable to accommodate taller or shorter articles on a conveyor.

Description:
This application incorporates by reference US application number not yet assigned by the same inventor filed on the same date. The title of the application is Perforated Film Wrapping Machine. 
   FIELD OF THE INVENTION 
   This invention relates to a film wrapping an article on a conveyer using a flying rod. The height of the flying rod is adjustable to accommodate articles of different heights. 
   BACKGROUND OF THE INVENTION 
   The prior art teaches wrapping an article with a film on a conveyor using a rod or a bar or roller. Usually a flying rod is used to wrap the film over the article. The flying rod revolves around the conveyor. This requires the rod to pass through the space between the adjacent conveyors. The height of the rod is fixed. Therefore, there are limits on the height of articles that can be wrapped with the conventional film-wrapping machine. These film-wrapping devices are usually found on a lap seal machine. 
   SUMMARY OF THE INVENTION 
   The objective of this invention is to be able to change the height of the wrapping bar so that articles of different heights can be accommodated. This is accomplished by making the height of the wrapping bar adjustable to accommodate taller or shorter articles. This requires changing the revolution of the flying rods to accommodate the height of the article while allowing the rods to pass between adjacent conveyors. 

   
     THE DRAWINGS 
       FIGS. 1-3  show the conventional movement of a flying rod moving film over an article on a conveyor between two adjacent conveyors. 
       FIGS. 4-6  show the movement of the flying rod with an adjustable height structure to wrap an article and moving between the adjacent conveyors. 
       FIG. 7  shows an acme screw with an adjustment knob that can be rotated. 
       FIG. 8  shows a shaft attached to the acme screw that can be moved along the acme screw by an adjustment screw. 
       FIG. 9  shows a shaft rotating the acme screw by a pulley. 
       FIGS. 10-13  show the linkage between the moving parts of the film wrapping machine. 
       FIG. 14  shows the position of the acme screw when the flying rod is going between the conveyors. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1-3  show a conventional lap seal conveyor system. The article  2  is transferred from conveyor  5  to conveyor  4 . Prior to moving article from conveyor  5  to conveyor  4  a film is fed onto the transfer belt of conveyor  4 . The length of the film fed on to conveyor  4  is about half the length of the article. This portion of the film is commonly referred to as a flap. The total length of the film is pre cut to a length that allows wrapping of the article and overlapping the flap. 
   The article is moved onto conveyor  4  so that the article rests on the top of the flap  41  lying on the transfer belt of conveyor  4 . While the article is resting on the flap  41 , the rod  7  attached to arm  3  picks up the pre cut film  40  from underneath the conveyor  4  by passing through the opening between conveyor  4  and  5 . Then the rod passes through the opening between conveyors  4  and  8 . The article pushes the remainder of the film under the article so that the flap is overlapped. From there the article is transported to a heat shrink machine that seals the overlap and shrinks the film over the article. 
   The rods  7  and  9  are attached perpendicular to arm  3 . The rotation of arm  3  about axis  6  causes the rods  7  and  9  to rotate around the conveyor. The position of the rods is equidistant to axis of rotation  6 . The rotation of the rods is synchronized with the movement of the article on the conveyor. Because the rods are fixed in height, wrapping articles of different heights is a problem in the art. 
     FIGS. 4-7  shows means to change the height of the rod with respect to the article while maintaining a geometry that allows the rods to go between the spaces of the adjacent conveyers  5  and  8 .  FIG. 4  shows rods  7  and  9  attached to arm  3  and rotating about axis  6  as in  FIGS. 1-3 . Arm  3  is attached to arm  12 . Arm  12  is able to pivot at point  17 . One end of shaft  15  is attached to arm  12 . The other end is attached to the actuator  16 .  FIGS. 7 ,  8  and  9  shows the shaft  15  attached to a screw in the actuator (Acme screw)  16 . By turning the adjustment knob the screw moves the position of shaft  15  with respect to the actuator  16 . Actuator  16  is mounted to rotate 180 degrees about axis  19 . The rotation of the actuator about axis  19  is by a drive pulley  31  mounted on shaft S 4  which is attached to the actuator at point  19 . 
   The rotation of the actuator places the rods  7  and  9  in a position where the rods can go between the adjacent conveyors while allowing the height of the rod over the article to be changed. The distance between the adjacent conveyors is usually about 0.5 inches. 
   Moving the adjustment knob  23  so that the shaft  15  is further away from the axis of rotation of the actuator causes the main arm  12  to be raised. Raising the main arm  12  causes fixed point  6  to raise, thereby causing rod  7  and  9  to be raised. Likewise, moving the adjustment knob  23  so that shaft  15  is closer to the axis of rotation of the actuator causes the main arm  12  to be lowered. Lowering the main arm  12  causes point  6  to be lowered, thereby causing rod  7  and  9  to be lowered. The position of the actuator shown in  FIGS. 4 and 5  places the fixed point  6  of arm  3  in the proper position to allow the rods  7  and  9  to go between the adjacent conveyors. 
   The use of an actuator is a preferred embodiment. Actuator  16  can be replace by any rotating member that would be allow rod  15  to be moved closer or further from the axis of rotation. For example the member might be slotted that would allow rod  15  to be moved to desired position.  FIG. 9-14  show the linkage between the movement of the article  2  on the conveyor  4  and the rotation of the flying rods  7  and  9  and the rotation of the actuator  16 . Shaft  1  which rotates proportionally to the position of the article on the conveyor. Actuator  19  is rotated by a pulley  31  on shaft S 4  which connected by a belt to drive shaft S 1  via pulley  30 . This pulley  31  is connected to the pulley  30 . Arm  3  attached to shaft S 3  is connected to shaft S 2  by pulley  34  and pulley  35  on shaft S 3 . Shaft  2  is connected to shaft  1  by pulley  33  and pulley  32  on shaft  1 . The pulleys are connected by drive belts. In a preferred embodiment, shafts S 1  and S 2  and S 3  are rotating at the same speed. Shaft S 4  is oscillating so that in one revolution of shaft S 1  the rotating member is rotated  180  and rotated back  180  to its original position. This accomplished by pulley  30  having a diameter 2 times larger than pulley  31  and having the proper linkage to achieve the oscillation. By selecting the proper pulley ratios the synchronization of the rotation of the flying rods and the actuator with the movement of the article on the conveyor can be achieved to wrap articles of different heights.