Composite can registration

In a method for producing spirally wound containers wherein a plurality of layers of material are spirally wound onto a mandrel to form a tube, the outside layer of said material being a label having a repeating pattern and equally spaced reference marks located along its length, wherein sections of said tube which include a plurality of container bodies defined by said pattern are severed in register with said pattern by cutting means connected to a reciprocating carriage which moves parallel to the longitudinal axis of said tube, wherein registration is controlled by maintaining the long term phase relationship between the motion of said carriage and the sensing of the passage of said reference marks past a reference point, and wherein said sections of the tube are later recut into individual container bodies having a fixed length, an improved method wherein said cutting means are carried by a movable sled connected to said carriage and movable parallel to the longitudinal axis of said tube comprising the steps of:

• determining a first residual registration error as a function of variations in the length of said sections of the tube;
• determining a second residual registration error as a function of factors other than variations in the length of said sections of the tube;
• generating a position change signal corresponding to one-half of said first residual registration error and all of said second residual registration error;
• and
• positioning said sled with respect to said tube in response to said position change signal shortly before cutting, so as to minimize the registration error with respect to said container bodies.

In an apparatus for forming spirally wound containers from a plurality of spirally wound layers of material, the outside layer of which is a label having a repeating pattern which includes a plurality of generally equally spaced apart reference marks located along its length, wherein means are provided for spirally winding said material onto a mandrel to form a tube, wherein cutting means connected to a reciprocating carriage which moves parallel to the longitudinal axis of said tube are provided for severing sections of said tube in register with said pattern, and wherein registration is controlled by means for maintaining the long term phase relationship between the motion of the carriage and the sensing of the passage of the reference marks past a reference point, the improvement comprising:

• a movable sled located on said carriage and carrying said cutting means, said sled being movable parallel to the longitudinal axis of said tube;
• means for determining a residual registration error;
• means for generating a position change signal which is a function of said residual registration error;
• means for generating a sled travel signal as a function of the amount of travel of said sled which has occurred before cutting begins;
• means for generating a repositioning error signal representing the difference between said position change signal and said sled travel signal;
• means for comparing said repositioning error signal to preset limits;
• means for positioning said movable sled with respect to said tube before cutting in response to said position change signal so as to minimize the registration error with respect to said pattern;
• and
• means for rejecting the section of tube which was cut off if said repositioning error signal exceeds said preset limits.

In an apparatus for forming spirally wound containers a plurality of spirally wound layers of material, the outside layer of which is a label having a repeating pattern which includes a plurality of generally equally spaced reference marks located along its length, wherein means are provided for spirally winding said material onto a mandrel to form a tube, wherein cutting means, connected to a reciprocating carriage which moves parallel to the longitudinal axis of said tube, are provided for severing sections of said tube which include a plurality of container bodies defined by said pattern, said sections being severed in register with respect to said pattern and later being recut into individual container bodies, and wherein registration is controlled by means for maintaining the long term phase relationship between the motion of said carriage and passage of said reference marks past a reference point, the improvement comprising:

• a movable sled located on said carriage and carrying said cutting means, said sled being movable parallel to the longitudinal axis of said tube;
• means for determining a first residual registration error which is a function of variations in the length of said sections of the tube;
• means for determining a second residual registration error which is a function of factors other than variations in the length of said sections of the tube;
• means for generating a position change signal which corresponds to one-half of said first residual registration error and all of said second residual registration error;
• and
• means for repositioning said sled in response to said position change signal, so as to minimize registration error in each container when said sections are recut into individual containers.

In an apparatus for forming spirally wound containers from a plurality of spirally wound layers of material, the outside layer of which is a label having a repeating pattern which includes a plurality of generally equally spaced apart reference marks located along its length, wherein means are provided for spirally winding said material onto a mandrel to form a tube, wherein cutting means connected to a reciprocating carriage which moves parallel to the longitudinal axis of said tube are provided for severing sections of said tube in register with said pattern, and wherein registration is controlled by means for maintaining the long term phase relationship between the motion of the carriage and the sensing of the passage of the reference marks past a reference point, the improvement comprising:

• a movable sled located on said carriage and carrying said cutting means, said sled being movable parallel to the longitudinal axis of said tube;
• means for determining a residual registration error, including
• means for generating a signal which is a function of the amount of carriage motion occurring between the time a predetermined reference mark was expected to be sensed and the time said predetermined reference mark was actually sensed;
• means for generating a position change signal which is a function of said residual registration error;
• and
• means for positioning said movable sled with respect to said tube before cutting in response to said position change signal so as to minimize the registration error with respect to said pattern.