Design of an Active Wire Rope Tensioner

Abstract

This thesis presents the design process of an active wire rope tensioner, a device designed for cranes, that serves two primary functions. Firstly, it increases the tension in the wire rope during spooling, ensuring neat and tight winding on the drum to reduce damage to the wire rope and cutting-in problems. Secondly, it reduces the required lower block weight, thereby improving the crane's load curve.

The research has commenced with a study of relevant background information and working principles. A thorough literature and patent review has followed, revealing a gap in the state-of-the-art of tensioning devices that both prevent cutting-in and reduce the required lower block weight. In the conceptual design phase, seven innovative concepts have been generated based on the literature review and current principles. These concepts have been assessed for their capability to meet the requirements and their performance against the key performance indicators (KPIs). Consequently, five concepts remain, with the clamping track concept emerging as the most promising.

The clamping track concept utilizes a chain drive with clamps attached to it that press on the wire rope. By applying force to the chain, the tension in the wire rope can be manipulated. Detailed development of the clamping track concept has yielded a conceptual design with three potential deployment scenarios, each requiring a slightly different version of the active wire rope tensioner and offering distinct advantages and disadvantages. Scenario 1 offers the greatest possible lower block weight reduction but comes with the cost of a more complex and riskier system. Scenario 3 does not allow for any lower block weight reduction but is simpler and safer. Scenario 2 strikes a balance between the two.