Road surface is left undisturbed by .
by...
ONVENTIONAL methods of laying cables and pipes under a road entail breaking up the road surface, burying the cable and finally restoring the surface to its original state. To avoid the cost and inconvenience to traffic that this work involves, a Swedish company has developed a new system which enables the cable to be pulled through a pipe driven through the road foundation, under the roadway.
The company, Atlas Copco of Stockholm, working in collaboration with the Sandvik Steel Works and Keyser & Co., have produced three different types of equipment for the job, the first being the Promec C-301 drilling rig with a rock drill. This is built up on standard components used in the mining industry and can pene- trate any type of ground.
Work starts with the setting-up of the unit on one side of the road and below its surface. A hole is drilled with a conventional bit and extension rods. At the same time, a thin-walled pipe is fed in from the back. The
NEW CABLE
LAYING METHOD
drilling equipment rotates inside the pipe and when one length of piping has been fed in, the rock drill is stop- ped. a new length and drill rod are connected and drilling can proceed.
Percussion Equipment
The second type of equipment used works on the percussion principle. It consists of a standard pneumatic breaker mounted on an auto-feed de- vice and is suitable for use in gravel, clay and moraine. Minor stones are
broken up by the tip fitted on to the front pipe.
The second type of equipment used also works on the percussion principle. The driving is done by a petrol- driven drill, independent of any com- pressed air supply. This unit is easily transported and easy to erect and handle. The pipe is driven for- ward by a combination of blows and vibration without rotation. An adapter transmits impact energy to the pipe and the feeding is done by means of two feeding bars.
{
Promec C-301 drilling rig
being used for
road penetration
under-
Far East BUILDER, April 1968.
Petrol-driven drill in op- eration. This system uses the percussion principle
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