Web tension control system

A tension control system comprising:

• (a) a hollow cylindrical roller having an exterior surface engageable with a moving web;
• (b) a shaft disposed within said hollow roller, said shaft having opposite end portions;
• (c) a spherical bearing assembly mounted on said shaft between said opposite ends thereof, said bearing assembly including a first bearing element having an inner surface fitted onto said shaft and an outer truncated spherical bearing surface formed with a first slot therein, and including a second bearing element having an inner truncated spherical surface formed with a second slot therein and positioned in sliding abutment with said outer truncated spherical bearing surface of said first bearing element, said first and second slots being located on said inner and outer spherical bearing surfaces so as to be aligned with one another at one predetermined relative position of said first and second bearing elements;
• (d) a wafer element selectively insertable in said first and second slots when they are aligned with one another;
• and
• (e) a roller bearing mounted between the inner surface of said hollow cylindrical roller and the outer surface of said second bearing element to permit relative rotation of said hollow cylindrical roller and said shaft,
• whereby said moving web can move across said rotating hollow cylindrical roller and said roller can pivot in all directions relative to said shaft to compensate for variations in tension in said moving web when said wafer element is removed from said first and second slots, and can pivot in only one predetermined plane relative to said shaft when said wafer element is inserted in said first and second slots.