Apparatus for heating film webs simultaneously in two axial directions

An apparatus for treating a film web simultaneously in two axial directions, comprising endless tentering chain means, including chain links and chain link journal shafts interconnecting said chain links, chain track means for supporting said endless tentering chain means along both edges of said film web, tentering clamps (20) for gripping a web edge, means for rigidly mounting said tentering clamps to said tentering chain means at a first spacing (y) between any two tentering clamps directly following each other in a row, and means for varying said spacing (y), said means for varying comprising, as part of said chain links, a pair of chain links for each of said tentering clamps, each pair of chain links including a first freely pivotable chain link (8) and a second freely pivotable chain link (7), and, as part of said journal shafts, a first journal shaft (3b) for pivotally connecting said first chain link (8) to one tentering clamp of said two tentering clamps, a second journal shaft (3a) for pivotally connecting said second chain link (7) to the other tentering clamp of said two tentering clamps, and a third journal shaft (10) for journalling said first and second chain links (8 and 7) to each other to bridge said first spacing (y), one of said first and second chain links forming a bellcrank lever having a chain link arm (8) and an angled lever arm (9) extending at an angle relative to a chain moving direction, said third journal shaft (10) passing through an intersection between said chain link arm (8) and said angled lever arm (9), said means for varying further comprising a guide roller (1) rotatably secured to a free end of said angled lever arm, and guide control track means (16) arranged for moving said guide roller (1) to position said first and second freely pivotable chain links (8,7) at an angle relative to each other, whereby said first spacing (y) is varied to a second spacing (x) depending on a distance between said guide control track means and said chain moving direction of said tentering chain means.