to the reacting shaft wall and at least one second stage jack a cylinder of the second stage jack being connected to cylinders of the first stage jacks application_number US 70634085 A description as shown in fig1 a pipe propelling device 10 according to the present invention comprises two sets of jack assemblies 12 14 spaced from each other in a vertical shaft and extending laterally in the direction of propelling the pipe of the vertical shaft both jack assemblies are slidably mounted on a pair of frames 16 disposed on the bottom of the vertical shaft and extending laterally the frames 16 are made of h type steel and interconnected by a plurality of connecting members 18 made of h type steel arranged longitudinally spaced from each other also the frames 16 are on the rear ends fixed by bolts to a box like reacting support 20 fixed to the reacting shaft wall of the vertical shaft see fig2 and 3 as shown in fig1 to 3 each jack assembly comprises a pair of first stage jacks 22 24 arranged spaced from each other vertically and a second stage jack 26 disposed between the first stage jacks said first and second stage jacks.