| 摘要 |
In order to be able to operate also in synchronism a two-stage telescopic, jack which can be used in an automatically-sequenced control mode, it is proposed to provide the first stage (12) of the telescopic jack with a top plate (126), to short-circuit the annular space (114) of the first stage (12) with the inner space (133) of the second stage (13) cut off by the top plate (126) of the first stage, and to provide a third pressurized line (23) connected to the annular space (124/124') of the second stage, formed by the short-circuited partial regions (124/124') produced by the top plate (126) of the first stage (12), said connection being effected via a telescopic feed-through (1131, 1232) extending between the base (111) of the jack (11) and the top plate (126) of the first stage (12); it must naturally be ensured that the annular space (114) of the first stage (12) and the inner space (133) of the second stage (13) are of equal volume. |
