A cord pulley is a small wheeled device that attaches to blinds or curtains. It provides leverage to pull cords or sashes by distributing cords across the ends of the blinds and allowing them to be moved using a downward or upward pulling motion. By permitting smooth operation, the pulley can keep cords from tangling with each other, causing the blinds to furl unevenly or get stuck. The smooth, angled surfaces along its spooling wheel help the cord pulley reduce wear and tear on cords that may be used several times daily.
Usually, one pulley is employed per lift cord on blinds or curtains of different varieties. This pulley is essentially a small wheel on an axle connected to a fixed or movable base. A groove runs between opposing flanges on the edge surface of the wheel. Like most pulleys, it transfers rotational motion and reduces pulling forces needed to do a certain amount of work. Pulleys may work in conjunction with other pulleys to further reduce forces. A cord pulley is essentially a fixed pulley in that it does not shift positions, though some may swivel in their bases.
These devices range in size from small fittings to medium or larger caster-style types for heavier loads, such as with Roman or Austrian-style shades. Cords may feed into the wheels directly, which turn freely and may be locked with a ratchet and pawl mechanism, activated when used in a certain drawing angle. Other units feed to traverse rods; these are rods of wood or plastic that hang from the pulley. The rods sit in a fixed mount and are turned by hand; turning force is transferred as a pulling motion through a pulley. Use of these rods reduces tangling as well as unsightly cord bunching. Rods also provide a trim appearance as a subtle but noticeable decorative element.
Typically composed of lightweight metals or plastic composites, cord pulley products are low-cost technologies that provide varying rates of strength and cord accommodations. Some may extend on swiveling arms to increase the range of leverage angles and reduce forces against rivets, screws, or other fastenings. Typical pulleys are rated for specific force and shade weight ranges. Festoon cord pulley devices hang loosely on an eyelet to permit more flexible range of motion, while window drape and blind cord pulleys extend from arms to permit easier hand purchase of draw cords from curtains. Others may be fixed inside wheel housings to add further decorative flourishes to the setup.