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US 4,290,764 AGranted
Method and apparatus for folding a cardboard sheet along a straight fold line
AssigneeHoogovens Ijmuiden, B.V.
InventorJan Middel
Life of this patent
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AssigneeHoogovens Ijmuiden, B.V.
InventorJan Middel
Estimating the term…
The problem of loss of strength in carboard along a line of fold due to stretching and breaking of fibres on the outside of the fold is overcome by providing a machine having a support surface against which the sheet of cardboard which is to be folded is held by an element which has a knife edge. The support surface is provided by a taut flexible sheet material which extends around a rotatable and movable roller. On operation of the machine, the roller is moved around the knife edge, its longitudinal axis being kept parallel to the knife edge, thereby making a fold in the sheet and the cardboard. The flexible sheet which contacts the cardboard has a high coefficient of friction with respect to cardboard. The restrains the cardboard fibres on the outerside of the cardboard as the fold is made preventing their stretching and breaking and thereby providing an unweakened fold.
Method of folding a sheet of cardboard along a straight fold line, comprising the steps of
An apparatus for folding a sheet of cardboard along a straight fold line, comprising a first element having a straight edge adapted to define the fold line, a support surface for the cardboard sheet and a second element movable in a path close to said straight edge of the first element to fold a cardboard sheet located between the first element and the support surface around the said straight edge in order to form the fold line in the cardboard sheet, the improvement that said support surface is provided by a flexible web maintained under tension and lying between said second element and said first element, means for moving said second element in a curved path about said straight edge to engage said web and simultaneously bend said web around said edge of the first element together with the cardboard sheet, the surface of said web which engages the cardboard having a high coefficient of friction with respect to said cardboard.
Apparatus for folding a sheet of cardboard along a straight fold line, comprising
Dependencies are inferred from the claim text.