Helical folder for paperboard blanks

Apparatus for folding paperboard blanks fed one by one in timed sequence into said apparatus, each of said blanks comprising a first panel and a second panel separated by a crease, said folding comprising folding said first panel with respect to said second panel along said crease from an initial angular relationship between said panels denoted an entrance angle to a resulting angular relationship between said panels denoted an exit angle, said apparatus comprising

• (a) conveyor means adapted to transport said blanks one by one in a direction of travel with said second panel being moved along a plane of travel;
• (b) elongated helical folding means comprising
• (i) helical blank contacting means having a longitudinal axis extending generally in the direction of travel, and
• (ii) shaft means which supports said helical blank contacting means, which extends coaxially with said longitudinal axis, which is rotatable to rotate said helical blank contacting means about said longitudinal axis, and which has ends positioned to accommodate said entrance angle and provide said exit angle;
• (c) means to rotate said shaft means to rotate said helical blank contacting means about said longitudinal axis in fixed operating ratio with conveyor speed;
• the configuration and positioning of said elongated helical folding means and said fixed operating ratio being adapted to provide initial contact between said helical blank contacting means and said first panel without impact and at only an interior portion of said first panel, and to provide thereafter, as a blank is being transported, continuous contact between said helical blank contacting means and only interior portion of said first panel, to fold said first panel smoothly toward said second panel.