Roli Cradle for Pipe Layer

When it comes to accessories, it is sometimes possible to take a basic idea and have a go at creating something by hand. That is the case with the Roli Cradle, a lifting device used mainly in pipe line construction to transport and lower pipe sections into a trench. The cradle makes an ideal accessory for a pipe layer machine and is fairly easy to produce with only basic tools required.

To start with, the main structure is comprised of tubular sections with a straight member, both easily constructed from plastic card and tubing. To get the basic shape, two 8mm holes were drilled, followed by several 3mm holes to form the lifting slot, using a sharp knife to remove the material and finish off the shape. Once cut to shape, the two tubular sections are glued into place, using a thin lower cross piece to provide more rigidity. The final step is to drill several 1mm holes on the upper surface of the tubes and insert small rods to hold the cables in place.

Using a length of 2mm and 4mm plastic tubing, it is possible to cut a number of lengths of each to form the actual rollers and spacers. In this design, I have used pairs of 7 main rollers with 6 spacers but other combinations are possible. Once cut to uniform lengths, four pairs are connected together using a small flat piece of plastic with holes drilled to align with the holes in the rollers. This keeps the rollers evenly spaced and should be the same width as the main tube dimensions (8mm between centres). The final step is to thread the rollers and spacers to produce two complete sets. Each needs to be set to the same length to allow a suitably sized pipe to balance correctly. This is a rather easy scratch built project and once painted, looks quite effective when added to the hook block of a suitable pipe layer, shown here fitted to the Liebherr RL64 from NZG