Abstract: A retractable cord queue barrier system uses a spring-biased pulley refraction mechanism acting on a stretchable cord. A constant-force coiled metal spring is used, such that the retraction force on the cord does not increase as the cord is extended—as it would for a helical spring governed by Hooke's Law. The use of a constant-force spring avoids abrupt snap-back of the extended cord when released, as well as the need for excessive pulling force on the cord as it approaches full extension, which tends to cause the stanchion to tip over. Dynamic balance between the contractive force of the stretchable cord and the retractive force of the constant-force spring achieves a taut but not unyielding tension in the interconnecting cords between stanchions.

Abstract: A retractable cord queue barrier system uses a spring-biased pulley refraction mechanism acting on a stretchable cord. A constant-force coiled metal spring is used, such that the retraction force on the cord does not increase as the cord is extended—as it would for a helical spring governed by Hooke's Law. The use of a constant-force spring avoids abrupt snap-back of the extended cord when released, as well as the need for excessive pulling force on the cord as it approaches full extension, which tends to cause the stanchion to tip over. Dynamic balance between the contractive force of the stretchable cord and the retractive force of the constant-force spring achieves a taut but not unyielding tension in the interconnecting cords between stanchions.