Web stretching apparatus

An apparatus for stretching a web in which longitudinal stretching of the web is accomplished comprising:

• a pair of spaced apart rotatable members each having an axis of rotation;
• means for rotating said members in unison about their axes of rotation;
• a plurality of angularly spaced primary clamps carried and guided by each of said members for generally radial movement outward from a primary web engaging position;
• means for actuating each of said primary clamps at its primary web engaging position when moved into overlapping alignment with the edges of a web transported between said members for successively engaging the edges of the web;
• a plurality of angularly spaced secondary clamps carried and guided by each of said members for generally radial movement outward from a secondary web engaging position radially spaced from said primary web engaging position, said secondary clamps being angularly interposed between said primary clamps;
• means for actuating each of said secondary clamps at its secondary web engaging position when moved into overlapping alignment with the intermediate edges of the web extending between a pair of web engaged primary clamps for successively engaging the intermediate edges of the web;
• a stationary cam associated with each of said members and adapted upon rotation of said members to successively contact and cam (1) each of said primary clamps radially outwardly from its primary web engaging position whereupon initial stretching of the web takes place, and (2) each of said secondary clamps radially outwardly from its secondary web engaging position whereby continued stretching of the web occurs with minimum scalloping of the web edge,
• each of said primary clamps being actuated at a primary web disengaging position for successively disengaging the edges of the web,
• means operative in response to rotation of said members to return said primary clamps after disengagement to their primary web engaging positions,
• each of said secondary clamps being actuated at a secondary web disengaging position for successively disengaging the intermediate edges of the web, and
• means operative in response to rotation of said members to return said secondary clamps after disengagement to their secondary web engaging positions.