CABLE LAYING.

Otago Daily Times, Issue 19783, 7 May 1926, Page 2

CABLE LAYING.

A SOUTHLAND INVENTION. DEPARTMENTAL OFFICIALS ‘ INTERESTED. Interesting pioneering work in connection with subterranean cable-laying was carried out at on Wednesday (says the Southland Tin.es), when Mr Joseph G. Kirby, of Wyndham, gave a practical demonstration of the capabilities of a remarkable contrivance for cable-laying which he has invented and patented. Primarily, the demonstration was staged for the benefit of various Government departmental officials, and although previous trials had been held at .Gore, this was the first occasion on which a cable was actually laid with the invention. A permanent cable was laid along the north side of Balaclava street for the Telegraph Department, and the operations were viewed with interest by Mr G. S. Plank (Dominion Inspecting Engineer, Wellington), Mr L. L- Macey (Telegraph Engineer for the Otago district), Mr A. Scott (Telegraph Engineer for the Southland district), Mr W. E. Pearce (of the Public Works Department, Invercargill) and Captain E. L. G. Bown, of the D. nee Office, Gore. These officials will report on the demonstration and the invention to their various departments. The apparatus is of simple design, and is constructed on the lines of a drain plough. A substantial four-wheeled chassis is surmounted towards the rear with the cable spool and its appurtenances for adjustment. The cable-laying appliances proper bear a close similarity to a drain plough. A heavy centre beam (with deptj) ami balance controls operated from the front) draws the “planting” blade, a rudder-like implement with a depth of approximately three feet and a length from heel to toe of four feet six inches. Additional chain controls are attached to the top of the blade, those going round _on each side of the chassis and connecting with a spindle in front. This system of control is identical with the ''steering gear of a boat. The cable is fed from the spool through a passage in the blade, entering between rollers at the top and emerging over another roller at the heel. The cable layer is drawn by traction engine. For the purposes of the demonstration.a trench was first dug at the point of commencement to adjust the blade to 'the desired depth, this being a precautionary measure in view of the fact that it was the first occasion on which a proper cable was being handled. The cable was to be laid at a depth of 18 inches, and within an hour after the commencement of laying operations over a quarter of a mile of cable had been entrenched. The apparatus worked smoothly throughout, and the demonstration was completed without a hitch The passage of the blade through the ground is marked by a slight ridge, and apart from this the ground resumes its normal formation after the cable has been planted. To demonstrate the capabilities of the invention to the fullest the apparatus was drawn across a couple of solidly gravelled roads, and these compact masses were negotiated with the same case as was the turf land along the roadside. The digging of the trench at the outset was merely undertaken as a safeguard to the success of laying the first subterranean cable, and after this had been accomplished the blade was lifted and set on a new route above the ground to demonstrate that it will “dig-in” automatically. The central beam to which the blade is attached, by reason of the swivel attachment to the chassis, can be elevated to allow the blade to _ rest on the ground. Once the machine is in motion, however, the weight of the beam forces the blade into the earth, and within a few yards the requisite depth is obtained. The method of release is equally simple. The hindermost of two bolts which attach the blade to the beam is removed and the forward one eased. The apparatus is hauled forward and the blade, taking the line of least resistance, emerges heel first from the ground and can be wedged in a position free from earth obstructions. After the demonstration the cable was unearthed at several points, when it was found that its depth varied little from the requisite 18 inches ( Although operations were in progress tor the best part of an hour, the actual time taken to lay the cable was only 26 minutes. The traction-engine made a series of stationary pulls, and considerable time was spent in unwinding the steel rope after each pull.