The Cushionloks® system consists of a rectangular bar that fits through a guide on one leaf tip and into a receiver on the other. This allows shear load transfer from one leaf to the other, so the leaf tips deflect uniformly during the passage of vehicular traffic.
Stiff disc springs support the wear shoes in the guide and receiver housings and ensure firm, continuous contact between the bar and shoes. Shock loads to the bar are reduced, zero clearance exists between the bar and shoes, and uncontrolled bounce of the leaf tips is eliminated.
The first Cushionloks® were installed and put into operation February 1995 on the Bellaire Causeway Bascule Bridge, Pinellas County, Florida. Since that time, many have been installed on bridges varying sizes and traffic loading. Lock bar sizes range from 4 x 6 inches to 7 x 10 inches for shear load transfers from 25,000 lbs to 120,000 lbs. per lock bar. In all installations the maintenance savings have been significant because bar and shoe wear has been reduced and emergency maintenance has been minimal. The leaf tips continue to deflect uniformly and without pounding or noise during the passage of heavy traffic.
A number of improvements has been incorporated into the current production of Cushionloks® guide. The most significant is the addition of screw adjustable spring settings. Now all preload is set by simply tightening a threaded cartridge. This way, preload can be added or subtracted at any time without removing the lock bar or shoes dissembling the spring stacks.