Importance

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Abstract

An operator for a window or like shade serves to turn a shade roller to a new desired position as the result of a torque applied from a manually operable source, such as a chain operated wheel. The device includes a helical spring that is seated within a fixed bushing with its outer surface in contact with an inner cylindrical surface of the bushing. When torque is applied from the manually operable source, one overlapping end of the spring is moved away its other end to reduce the spring diameter and hence release any frictional engagement of the spring with the bushing, thus allowing the torque to rotate the spring, which rotation is transmitted to the roller. However, when no such manually applied torque is present, the spring and the roller remain effectively locked in position. Any torque applied from the roller due to the weight of a partly lowered shade acts to tend to increase the spring diameter and thus to ensure a binding frictional engagement between the bushing and the spring.

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First Claim