Patent ID: 8308037

Claim:
An apparatus for maintaining uniform tension across a width of a web, the apparatus comprising: a roller including a shaft about which the roller rotates, the shaft defining an axis of rotation; a first arm and a second arm each including a first end, the first end of the first arm being rigidly coupled to an end of the shaft of the roller, the first arm extending away from the axis of rotation of the roller in a first direction, the shaft of the roller and the first arm lying in a plane, the first end of the second arm being rigidly coupled to an opposite end of the shaft of the roller, the shaft of the roller and the second arm lying in the plane, the second arm extending away from the axis of rotation of the roller in a second direction that is substantially opposite to the first direction, the first arm and the second arm each including a second end; a plurality of devices, the second end of each of the first arm and the second arm being coupled to a corresponding one of the plurality of devices at a location that is at the same distance from the axis of rotation of the roller such that each device, when considered independently of the other device, is limited to two degrees of rotational freedom about two corresponding axes of rotation relative the arm to which each device is coupled, the two degrees of rotational freedom lying within the plane; and a plurality of links, each of the devices being pivotably coupled to a corresponding one of the plurality of links, each link including a first end and a second end, the first end of each link being pivotably coupled to the shaft of the roller through the device such that a first axis of rotation is defined, the second end of each link being pivotably coupled to a stationary frame such that a second axis of rotation is defined, the first axis of rotation and the second axis of rotation being substantially parallel to each other.