Light lock for roll dispensing container

Claim 1

In a container having a generally tubular casing member and a pair of laterally opposed end walls enclosing a chamber for a roll of strip material with a light-sensitive, abradable layer, the improvement comprising: a first elongated lip on the casing member extending in a direction substantially axially of the casing member; a second elongated lip on the casing member substantially parallel to said first lip, said second lip being movable toward and away from said first lip to form therebetween a variable width slot which (1) communicates with the chamber, (2) provides a path through which strip material may be tensioned and pulled from the chamber with its light-sensitive layer toward said first lip and (3) is curved partially about an axis that is transverse to the direction of movement of strip material being pulled through the slot and is located on the same side of said slot as said second lip; an annular recess on each of said end walls for receiving one end of the casing member and said lips, said annular recesses being enlarged in the region of said second lip for permitting movement of said second lip away from said first lip; means for rotatably supporting a roll of strip material in the chamber with resistance of the roll turning; and resilient means for urging said second lip toward said first lip to clamp in said curved slot a portion of the strip material between said first and second lips with a predetermined pressure, whereby tension produced in said strip material is pulling it from the chamber produces a resultant force which opposes the force of said resilient means to at least partially relieve the pressure of the light sensitive layer of the strip material against said first lip.