Screw jacks supplied by Drive Lines Technologies are being used in a
novel retracting altar platform mechanism devised by British Turntable
subsidiary, Hovair Systems for Lichfield Cathedral. The 38m3 floor
surface can be raised 300mm in two stages to form a platform for
services, then lowered to the surrounding floor level for concerts. Prior
to the installation, a bulky, demountable dais required considerable
effort to remove and replace; it also had a 'temporary' appearance.
Architect, Martin Stancliffe created the design for the Lichfield dais
and chose screw jacks rather than hydraulics for their clean and reliable
operation, and easy maintenance. The screw jacks supplied to the project
by Drive Lines were Inkoma precision units, which have a thrust range of
2.5 to 500kN. The new floor was built by WBM Restoration using closely
matched stones supplied by Lowe's Marble. The stones on the perimeter of
each section are 170mm thick to give a solid appearance when the platform
is in the raised position. The rest of the stones are 20mm thick and were
precisely cut to avoid gaps around the edges where the platforms rise.