GPO Vehicles


Make Land Rover
Model 88
Type Short Wheel Base Hardtop
Body Builder  
Use With Plumett Winch
Registration Number  
Fleet Number  
Date of picture  


A Land-Rover Mounted Winch
by M. DOHERTY
An Extract from the P.O.E.E.J Vol 63, page 31 (April 1970)

Until recently, most external cabling work has been performed by a trailer-mounted capstan-winch pulling a separate cabling rope. This requires at least two towing vehicles, one for the cable trailer and another for the winch. A Land-Rover station wagon with an integrally-mounted winch of new design has been developed to provide a truly mobile winch for cabling parties.

FIG. 1 Winch and take-up drum beside the driving seat

INTRODUCTION
Land-Rover station wagons have been used for several years by cabling parties as personnel carriers and towing vehicles. The need for a mobile cabling winch, preferably with its own captive rope, led to the fitting of a centrally-mounted “bull” winch in the Land-Rover station wagon Type 3. This unit, in conjunction with a cabling vehicle carrying tools and equipment, and towing the cable-drum trailer, is expected to be used for the majority of cabling work, until more sophisticated plant becomes generally available.

DESCRIPTION OF THE VEHICLE
The winch is mounted, with its take-up drum of rope, beside the driver in the centre of the vehicle and is driven by the vehicle engine through a power take-off (see Fig. 1). The cabling rope is fed under the vehicle through a pulley to the rear.
The winch controls, which are mounted at the rear near side of the vehicle to give the winch operator a clear view of the cabling operations, consist of a clutch lever and a winch gear-change lever, that allows the cable to be pulled-in or paid-out. The clutch lever protrudes beyond the rear door of the vehicle when in use (Fig. 2) and can be folded back when travelling. It is connected to the vehicle clutch hydraulically so that when raised the clutch is engaged and when pressed downwards the clutch is disengaged. The engine speed is also controlled by this lever. The clutch handle incorporates a safety button on its end which must be held depressed when the clutch is engaged. Release of this button whilst the clutch is engaged disconnects the engine ignition to stop the engine and winch. The clutch handle can be held in the disengaged position by means of a catch. In this position the emergency ignition cut-off button is inoperative so that the engine will continue to run.

The Land-Rover is also provided with a four-wheel brake locking system, which locks all the wheels during cabling operations. Jacks (Fig. 3) are provided at the rear of the vehicle to relieve its springs from loads imposed by cabling operations. A rope or cable guiding attachment (Fig. 3) is provided for use in joint boxes and manholes. It consists of a pair of stout parallel tubes to which are attached one large and one small pulley. The upper ends of these tubes are anchored to the vehicle by a bolt passing through an extension tube. When travelling, this tube is housed under the rear floor of the vehicle but is extended and pinned in position at the rear of the vehicle for cabling work. The end of the cabling rope is normally stowed on a hook positioned under the rear of the vehicle, and the rope guide attachment is secured on top of
the nearside seating position in the vehicle by fixing straps. (Fig. 2.)

FIG. 2 Winch controls and cable guides
stowed for travelling
FIG. 3 Rope or cable guiding attachment anchored
to vehicle by means of extension tube

WINCH DESIGN
The winch driving-mechanism consists of two “bull” wheels of equal diameter, each having several grooves round which the cabling rope passes (in the manner of a pair of multi-sheave pulleys) before being wound on the take-up drum. The two bull wheels are geared together and the mechanism works in a similar manner to a capstan winch except that the take-up drum applies the tension to the loose end of the rope. Since the rope runs in grooves on the bull wheels, there is no jumping of the turns as can occur on a capstan when the rope creeps towards the major diameter and suddenly slips back to the minor one. The bull winch operates smoothly under load and, because the rope is coiled automatically, requires only one man to operate it. It is also compact and self-contained and there is no need for separate reels of cabling rope.

The take-up drum is chain driven from the winch gearbox through a sprocket containing a slipping clutch which is preset to maintain a tension of 100 lb on the cabling rope as it leaves the bull wheels. This take-up drum contains 500 yd of polypropylene-covered steel-rope, 0.25in diameter, but may, if desired, be fitted with 450 yd of 8 mm steel rope. The winch drive incorporates a safety over-load clutch which is adjustable to the safe-working tension of the rope being used. For 0.25in rope this is 2,500 lb and for 8 mm rope 4,000 lb. During cabling work the Land-Rover gearbox is engaged in second gear with the transfer gearbox in neutral. This gives a cable speed of approximately 120 ft/mm with an engine speed of approximately 1,250 r.p.m.

CABLE PULLING
For normal cabling work, the rope or cable guiding attachment is first fitted to the rear of the vehicle and then lowered into the joint box or manhole. The cabling rope is then fed from the winch over the top pulley and under the lower one and attached to the drawrope in the duct. The other end of the drawrope is pulled out by a small self winding winch normally carried by the cabling vehicle. During paying out of the cabling rope, the bull winch must be run in reverse so that the bull wheels can pull the rope off the take-up drum. When the cabling rope has been drawn in by the drawrope, the cable is attached to it, the bull winch reversed, and the clutch lever raised to engage the clutch and pull in the cable. When the leading end of the cable reaches the winch position, it can be pulled round the large lower pulley to provide jointing overlap. An operator standing at the nearside rear of the vehicle during cabling, with his left hand on the control handle, is clear of the line of pull and is able to see both down into the box and in the direction of the far end of the duct. Radio communication can be used when cabling is in progress.

CONCLUSIONS
The mobility of the vehicle and the ease of operation have been favourably commented on by users. The Land-Rover can also pull a loaded cable-drum trailer with a total weight of 45 cwt.

Approximately 100 of the items have been purchased and are now being made available to the field.

BACK Home page BT/GPO Telephones A - Z Index Vehicles Home Page Quick Find All Telephone Systems

Last revised: January 05, 2004

FM