In 1988 Vulcan personnel visited what was then Leningrad to view the operation of a Soviet variable-eccentric moment vibratory hammer. The account of that is here. This is the field service manual for the hammer.
The hammer’s construction is interesting for a number of reasons:
- It did feature variable eccentric moment, which was done using weight shifting techniques when the hammer is stopped.
- It was an electric machine, which was common in the USSR at the time and elsewhere (especially Japan.)
- It had a true hydraulic clamp with a pump mounted in the suspension along with the electric motor, which transmitted energy to the hammer via a chain drive. The clamp may look primitive but it was an advance over the lever-type clamps (Foster was still using one at the time) and the mechanical clamps which were common in Soviet equipment.
The machine had eccentric moments ranging from 0 (yes, that’s possible with the variable moment) to 12 kg-m and a maximum dynamic force of 270 kN. That puts it between a Vulcan 400A and an 1150A. The manual also has a description of the “European” pick up and drive method for installing sheeting, which is also discussed here.