Apparatus for adjustment of the spacing of film drive assemblies in a tubular film forming device

In apparatus for forming a sheet of flexible material into a cylindrical shape, said apparatus including a generally cylindrical tube as a form for the sheet and further including spaced, generally parallel transport assemblies positioned on opposite sides of the tube, the improvement of a mounting and adjustment mechanism for controlling the movement and spacing of the spaced transport assemblies from a center line between the parallel assemblies, said center line generally coincident with the center line of the tube, said improvement comprising, in combination:

• at least one assembly support bar mounted generally transversely to the center line and extending over the range of desired travel of the assemblies;
• means for slidably mounting each assembly on the support bar for slidable movement toward and away from the center line;
• a spacing adjustment plate pivotally mounted adjacent the assemblies for pivot movement about an axis;
• a first arm pivotally connected to one assembly and extending generally parallel to the support bar to pivotally attached to the spacing adjustment plate at a first position which is a first fixed radial distance from the axis thereof;
• a second arm pivotally connected to the other assembly and extending generally parallel to the support bar to pivotally attach to the spacing adjustment plate at a second position which is a second fixed radial distance from the axis thereof, said first and second positions of attachment to the plate being on opposite sides of the plate axis whereby pivotal movement of the plate about its axis will simultaneously move the first and second arms in opposite directions and simultaneously in part opposite sliding movement of the assemblies on the support bar toward or away from the center line.