The vertical travel lead, referred to as “VTL” system, was first developed and patented by C.W. Bermingham in the1960’s. This lead system was developed in response to the fundamental limitations found in a fixed lead or swinging lead systems. The fixed lead system is well suited to level job sites with few obstructions and has the advantage of fast positioning of the lead. The hanging lead is very adaptable to different elevations and batter piles but takes much longer to position.
The Vertical Travel Lead was developed to combine the advantages of fixed leads, fast and accurate positioning, with the ability to adjust the height of the lead base up or down. The VTL lead is connected to the boom by a sliding connection which allows the lead to be elevated or lowered below grade. Many have recognized the advantages of the VTL system, and they have become the Industry standard in Canada, US Railway Construction, and many parts of the USA. The structural column of the VTL will resist bending in forward, aft, and side batter positions. The hydraulic spotter is very rugged and will transmit torque to the body of the crane rather than the boom. Bermingham Foundation Solutions manufactures many different models of Vertical Travel Leads and many of the first sets are still in service today.
The Bermingham Vertical Travel Lead system has been used for close to 50 years, with installations on every type of crane ranging from 40 ton truck cranes to 300+ ton crawler cranes.
The Bermingham lead columns are ruggedly built to withstand the daily abuses of pile driving. The spud type leads are available in a wide range of models for drilling and pile driving applications. The lightweight construction, combined with great strength, allow the leads to be used in any number of compound batters— up to 1:2 fore and aft and up to 1:3* side. The leads are simple to rig and un-rig—in some cases, piles are ready for driving in less than 3 hours from arrival onsite. When rigged, the lead can be used as a jib, allowing the crane to be used to set steel, unload trucks, etc., without un-rigging the crane or using a service crane. The slim design of the lead gives the crane operator a better view for faster driving and greater on-site safety. Bermingham Vertical Travel Leads are made to last, requiring little maintenance.
Bermingham Leads have been designed to increase the productivity of the pile driving operation. This is accomplished by minimizing the movement of the crane, and by decreasing the time spent placing the pile under the hammer and spotting of the pile. On a typical project, the actual productive driving time may be increased from an average of 50% of the work day to 75% or more.
At the “BIG DIG” in Boston, Nicholson Construction reported an increase in production from 5 insertions per day with a custom European piling rig to 12 insertions per day with a Bermingham Vertical Travel Lead on a Manitowoc M-250.
The spotter is an integral part of the Vertical Travel Leads. Bermingham spotters are capable of up to 30 degrees side-to-side movement with equalization cylinders that automatically keep the front face of the lead parallel with the front face of the crane. This is very beneficial when driving a straight bent of piles. Precise control of the hydraulic cylinders from within the crane cab gives precise placement of piles during driving. Both 2 and 3-stage spotters provide a wide range of sizes from 12 feet (3.66 m) retracted to 56 feet (17.07 m) extended. Custom spotters are also available to suit any job.