position shown with the upper end portion extending slightly above the channel irons 14 and 16 for reasons to be explained a pair of mounting plates 22 a and 22 b are welded to the respective corresponding welded edges of the channel irons 14 and 16 and each has an opening extending there through a pair of threaded rods 24 a and 24 b are welded to the plates 22 a and 22 b respectively and extend upwardly therefrom for reasons to be described 0010 fig2 depicts the apparatus of fig1 with a hydraulic drive assembly mounted thereon the reference numeral 26 refers in general to a driving or clamping assembly which includes a gripping sleeve 28 although not clear from the drawings it is understood that the sleeve 28 is in the form of a conventional u201c slip bowl u201d for grabbing or clamping over a pipe and as such includes three inner arcuate inserts not shown which are tapered in a vertical direction so that they will grab or clamp a pipe segment of a predetermined diameter during downward movement and slide over the pipe segment during upward movement in a conventional manner a pair of mounting plates 30 a and 30 b are connected to and extend from diametrically opposite portions of the sleeve 28 and each has an opening extending there through this clamping assembly 26 is disclosed in more detail in applicant 39 s u s pat no 4 765 777 the disclosure of which is hereby incorporated by reference a pair of hydraulic.