shown in fig6 the blade actuating means 26 is then slid down the unthreaded portion 29 of the deployment shaft 21 the shaft 21 is rotated in a first direction 45 by detachable rotation means 44 causing the internal threads of the blade actuating device 26 to engage with the threaded portion 28 of the deployment shaft 21 it may be necessary at this point to restrain the blade actuating device 26 from rotating with the shaft 21 in order to permit its axial translation downward towards the first collar assembly 10a until the tips 32 of the fingers 31b engage in tab slots 19 of the collar 11 fig7 the subsequent combination of the screw action on the blade actuating device 26 and the camming provided by the lower camming plate 24 results in the breakage of the strapping 43 if provided and the extension of the blades 12 into the walls of the hole 41 fig8 demonstrates how the blade actuating device 26 moves from the collar contact position 47 down near to the base of the hole 41 resulting in the blades 12 attaining their deployed position p2 the rotation means 44 may then be removed although the rotation means 44 as shown in the drawings depicts a manually operated dual ratchet arm the purpose could be served equally as well by appropriate power assisted means a second or upper collar assembly 10b is lowered into the hole 41.