| 摘要 |
In known support leg constructions of the type where the displacement of the support leg is carried out by means of a threaded rod, it is necessary that the pitch of the thread be not too steep as otherwise a rotation of one revolution of the rod requires too great a force. It is the object of the present invention to provide a support leg construction where the support leg is driven at a substantially greater rate when not loaded. The support leg construction of the invention is characterized in that the externally threaded rod (4; 4') has two portions (4a, 4b; 4a', 4b') with opposed pitch directions, one portion (4a;4a') being received in an internally threaded bore (12; 12') which is detachably non-rotatably connected with a holding means adapted to the supported means (2; 2') while the other portion (4b; 4b') carries an internally threaded element (6; 6'), to which one end of the support leg (7; 7') is pivotably adapted, and that a brace (10; 10') is pivotably attached with its ends to the support leg (7; 7') and to a means of attachment fixed relative to the supported means (11; 11'). |
