Patent ID: 8070660

Claim:
A device comprising: a roller assembly comprising: a roller of substantially cylindrical form having a first end and a second end; a substantially rectangular sheet affixed to the roller so that the sheet may be rolled up on the cylindrical surface of the roller; a tab attached to the sheet facilitating unrolling of the sheet by the user and preventing the roller from continuing to rotate once the sheet has been fully rolled up on the roller; an internally-splined member attached to the first end of the roller; a housing assembly comprising: a housing, having a first end and a second end, capable of releasably constraining the roller at its first and second ends so that the roller may move only rotationally about its axis; a spring, mounted at the first end of the housing, capable of supplying torque to the roller relative to the housing; an externally-splined member which mates with the internally-splined member allowing disengagement of the roller assembly from the housing assembly, and which, while the splined members are engaged, facilitates torque transmittal between the spring and the roller; a brake which prevents the spring from releasing energy while the roller assembly is disengaged from the housing assembly, wherein the spring and the externally-splined member are part of an assembly which is pivotally attached to the housing allowing the roller assembly at the first end to pivot on an axis perpendicular to the axis of the roller once the second end of the roller has been released from the housing thus allowing the roller assembly to be removed from the housing assembly.