Apparatus for forming a convoluted container sidewall

Apparatus for wrapping a blank about a mandrel to form a convoluted tubular sidewall, which comprises a mandrel, a clamping means associated with said mandrel to hold an intermediate portion of a blank therebetween, first and second folding wing means positioned to contact the outer surface of the thus held blank on opposite sides of said clamping means, means for rotating said first and second folding wing means about the axis of said mandrel to wrap the blank about said mandrel and for terminating the rotation of said second folding wing means about said axis before the opposite side margins of the blank are overlapped by the continued rotation of said first folding wing means about said axis, and means for sealing the thus overlapped side margins to thereby form a convoluted tubular sidewall;

• said means for rotating comprising a carriage, guide means for supporting said carriage, means for effecting forward and retractive motion of said carriage in said guide means in a reciprocating manner, a first driving element fixedly secured to said carriage, a second driving element mounted on said carriage and adapted to move between a first position and a second position with respect to said carriage, means for resiliently biasing said second driving element to said first position, first and second shafts, said first folding wing means being secured to said first shaft for rotation therewith, said second folding wing means being secured to said second shaft for rotation therewith, a first driven element secured to said first shaft for rotation therewith, a second driven element secured to said second shaft for rotation therewith, said first and second driven elements engaging said first and second driving elements, respectively, and stop means for terminating the movement of said second driving element during the final portion of the forward motion of said carriage so that the continued motion of said carriage with respect to said second driving element places said second driving element in said second position.