Variable height column with integral actuating means

摘要

A variable height column having a base, a midsection and an upper section. The base includes at least one upwardly extending guide shaft and the upper section includes at least one downwardly extending guide shaft. The midsection includes guide paths and bearings dimensioned for sliding engagement with the guide shaft. Hydraulic actuating means are provided to move the midsection vertically relative to the base and to move the upper section vertically relative to the midsection at the same rate to permit the uniform straightline extension and retraction of the column.