Apparatus by which horizontal and vertical blinds, pleated shades, drapes and the like may be balanced for "no load" operation

A blind unit comprising:

• a head rail;
• a plurality of blind members below the head rail;
• a lower rail below the blind members, each blind member and the lower rail having a normally lowermost operative position;
• a pair of spaced, parallel cords for suspending the lower rail below the head rail, said cords extending into the head rail, said lower rail being movable upwardly from said lowermost operative position thereof when an upward force is applied to the cords, said lower rail being operable to support a progressively greater or lesser number of blind members as the lower rail moves progressively upwardly or downwardly;
• and
• means for applying a variable, upwardly directed force to the cords with the force being substantially equivalent to the combined weights of the lower rail and the blind members supported on the lower rail when the lower rail is above its normal operative position, said applying means including a shaft rotatable relative to the head rail, a pair of spaced conical members on the shaft for rotation therewith, the conical members being aligned generally with respective cords, one of the cords being coupled with one of the conical members and the other cord being coupled to the other conical member, whereby the lower rail and the blind members can be raised or lowered by manually moving the lower rail upwardly or downwardly with a minimum of force applied to the lower rail.

A blind unit comprising:

• a head rail having a bottom;
• a plurality of blind members below the head rail;
• a lower rail below the blind members, each blind member and the lower rail having a normally lowermost operative position;
• cord means for suspending the lower rail below the head rail, said cord means extending into the head rail, said lower rail being movable upwardly from said lowermost operative position thereof when an upward force is applied to the cord means, said lower rail being operable to support a progressively greater or lesser number of blind members as the lower rail moves progressively upwardly or downwardly;
• and
• means for applying a variable, upwardly directed force to the cord means with the force being substantially equivalent to the combined weights of the lower rail and the blind members supported on the lower rail when the lower rail is above its normal operative position, said applying means including a carriage movable on the bottom, a constant force spring carried on the carriage, a shaft on the carriage, and a conical member coupled to and rotatable by the shaft, said shaft being coupled to the constant force spring for rotation thereby, said cord means being coupled to the conical member for raising and lower the blind members as a function of the rotation of the conical member by said spring relative to the carriage, whereby the lower rail and the blind member can be raised or lowered by manually moving the lower rail upwardly or downwardly with a minimum of force applied to the lower rail.

A blind unit comprising:

• a head rail;
• a plurality of blind members below the head rail;
• a lower rail below the blind members, each blind member and the lower rail having a normally lowermost operative position;
• cord means for suspending the lower rail below the head rail, said cord means extending into the head rail, said lower rail being movable upwardly from said lowermost operative position thereof when an upward force is applied to the cord means, said lower rail being operable to support a progressively greater or lesser number of blind members as the lower rail moves progressively upwardly or downwardly;
• and
• means for applying a variable, upwardly directed force to the cord means with the force being substantially equivalent to the combined wights of the lower rail and the blind members supported on the lower rail when the lower rail is above its normal operative position, said applying means including a leaf spring extending upwardly form the head rail, said cord means including a cord having an upper end, and a weight element on the upper end of the cord, said weight element being movable along the spring for deflecting the spring and varying the spring force on the cord as a function of the position of the weight element along the spring, whereby the lower rail and the blind members can be raised or lowered by manually moving the lower rail upwardly or downwardly with a minimum of force applied to the lower rail.

A blind unit comprising:

• a head rail;
• an indexing pin pivotally mounted on said head rail;
• a plurality of blind members below the head rail;
• a lower rail below the blind members, each blind member and the lower rail having a normally lowermost operative position;
• cord means for suspending the lower rail below the head rail, said cord means extending into the head rail, said lower rail being movable upwardly from said lowermost operative position thereof when an upward force is applied to the cord means, said lower rail being operable to support a progressively greater or lesser number of blind members as the lower rail moves progressively upwardly or downwardly;
• and
• means for applying a variable, upwardly directed force to the cord means with the force being substantially equivalent to the combined weights of the lower rail and the blind members supported on the lower rail when the lower rail is above its normal operative position, said applying means including a rotatable conical member having a spiral groove, said indexing pin being operable to keep the cord means in the groove of said member, whereby the lower rail and the blind members can be raised or lowered by manually moving the lower rail upwardly or downwardly with a minimum of force applied to the lower rail.

A blind unit comprising:

• a head rail;
• a plurality of blind members below the head rail;
• a lower rail below the blind members, each blind member and the lower rail having a normal lowermost operative position;
• cord means for suspending the lower rail below the head rail, said cord means extending into the head rail, said lower rail being movable upwardly from said lowermost operative position thereof when an upward force is applied to the cord means, said lower rail being operable to support a progressively greater or lesser number of blind members as the lower rail moves progressively upwardly or downwardly;
• and
• means including a leaf spring means for applying a variable, upwardly directed force to the cord means with the force being substantially equivalent to the combined weights of the lower rail and the blind members supported on the lower rail when the lower rail is above its normal operative position, whereby the lower rail and the blind members can be raised or lowered by manually moving the lower rail upwardly or downwardly with a minimum of force applied to the lower rail.