||WEK80 (5 ton chassis - 7 ton, 2 speed rear
||Pole Erection Unit (Experimental)
||King - Tel E Lect
||Installation of Poles
|Date of picture
LINE CONSTRUCTION UNIT (Experimental)
Reference:- I.P.O.E.E.J. Vol. 55, Part 4
Application Pole erection and recovery and all forms of overhead construction.
The unit described is the American Tel-E-Lect line construction unit and comprises a L.H. rear corner mounted derrick with pole hole borer, complete with utility body. The vehicle on which the equipment is mounted is a forward drive BMC 5/7 ton chassis/cab.
Stabilizing jacks are provided to maintain stability during lifting and boring operations.
All movements of the derrick, borer and jacks are hydraulically controlled from a control panel at the rear of the vehicle. An auxiliary hydraulic connection enables a pole jack and tamper supplied with the unit, to be operated from the hydraulic system. The derrick has full circle slewing and an extendable section on which the borer is mounted enabling holes to be bored at a radius of up to 23 feet. A fibre-glass cage can be mounted on the end of the derrick which enables overhead work to be carried out up to 34 feet above ground. A pole bolster has been added which enables a number of poles to be carried on the unit.
Derrick - 1 ton at 4 ft. radius height 34 ft. max. - 10 cwt. at 23 ft. radius height
3.5 ft. mm.
Pole Jack - 20 tons max. lift.
Borer - 12 in. and 16 in. diameter holes up to 8 ft. deep.
Dimensions - Travelling position - length 21 ft. 9 in.; Width 7 ft. 6 in.; Height 12 ft. 3m.
Weight - 7.5 tons unladen.
Transport Maximum permissible speed on Public Highway - 40 m.p.h.
Capital cost - £6,500.
The Post Office
Electrical Engineers Journal
Volume 55, Part 4 (1962)
A LINE-CONSTRUCTION VEHICLE
By W. C. Ward
A new type of utility vehicle equipped with
hydraulically-operated mechanical aids is described. These aids
include a derrick that can be rotated through 360°, a pole-hole
borer and a heavy-duty winch.
The line-construction vehicle is essentially a utility vehicle
for use by a general-purpose external working party. It is equipped
with a versatile power-operated derrick and a heavy-duty winch; a
pole-hole borer may be permanently attached to the derrick if
required. Units of this type have been in use in America for a
number of years, but until recently all had derricks, operated
either from the front or the rear of the vehicle, that were
incapable of rotation. While such units can operate efficiently
where there is space to manoeuvre, they would be severely
handicapped under the conditions usual in the British Isles, where
telecommunications external plant is almost invariably at the
roadside, and a large vehicle positioned across the highway could
not be tolerated in most situations where it would have to work.
Recently, corner-mounted rotating derricks have been developed in
America, and these enable the derrick and pole-hole borer to operate
over a large area with the vehicle parked at the kerb-side, and
there appears to be good scope for the operation of such equipment
in this country. A small number of similarly-equipped vehicles is
therefore being obtained for trial. Their use should remove much of
the heavy lifting and digging from external work and should increase
output. The fact that ample power is available for all operations
and that all loading and unloading can be carried out mechanically
should materially reduce accident risks.
THE NEW VEHICLE
The chassis is a 5/7-ton British Motor Corporation diesel
unit (i.e. a nominal 5-ton chassis with 7-ton 2-speed rear axle).
The drive from the rear of the engine is fed to a split-shaft power
take-off that enables full engine power to be used, if required, to
drive hydraulic pumps for operating the mechanical accessories. This
full-power take-off is in effect a mechanical switch that connects
the drive either to the back axle for propulsion or to the hydraulic
pumps for operating the mechanical aids; it is controlled
electrically from a switch in the cab. When the power
take-off is coupled to the hydraulic pumps, a brake is applied to
the shaft that drives the vehicle rear axle, to take the place of
The tandem hydraulic pumps circulate oil at 2,000 lb/in sq and 45
and 14.4 gallons/minute, respectively. Alternatively, if facilities
for operating a pole-hole borer are not needed, a single pump can be
used and a light-duty power take-off, known as an S.A.E. (Society of
Automobile Engineers) power take-off, is fitted to the side of the
The body is of plated-steel construction and of the open-well type,
with cupboards and lockers on the outside; the open well in the body
facilitates loading and unloading. The derrick and winch between
them can be used to load and unload all heavy stores and tools. The
side cupboards and lockers store the lighter tools, stores and
clothing; they give good access without the necessity for climbing
inside the vehicle, although they have the disadvantage that some
are necessarily on the side of the vehicle exposed to traffic.
The vehicle is intended for operation by two men, and the bodywork
is not designed for conveying additional staff. The vehicles will
probably be used in conjunction with 110-volt generating sets and a
range of electrically-operated tools, and these, together with the
other mechanical aids, should go far towards mechanizing the work of
external working parties.
The boom of the derrick is 17 ft 2 in. long from its centre of
rotation, but it has an extending section called a “stinger” that
extends the length to 2.5 ft. The derrick reaches from ft above the
ground to a maximum height of 33 ft. It has a head sheave over which
the winch-line passes and it can lift 2,000 lb at 23 ft radius. It
can be rotated continuously in either direction.
The heavy-duty winch is mounted immediately behind the cab and is
fitted with a wire-rope winch-line 300 ft long that can be passed
over the head sheave of the derrick or can be used for a direct
pull. The winch-line runs under a false floor in the vehicle body,
so that it is not obstructed by any tools and stores carried in the
The winch is driven by a hydraulic motor and has a maximum pull of
15,0001b. It has a shaft extension, accessible through an aperture
in the side of the vehicle body, to which can be attached a
wire-recovery reel or a capstan that can, for example, be used for
Hydraulically-operated stabilizers are provided at the rear end of
the vehicle to give the necessary stability when the derrick is in
use. These comprise an
outrigger on the corner of the vehicle where the derrick is fitted
and a simple hydraulic jack on the opposite corner.
The pole-hole borer is driven by a hydraulic motor of approximately
35 h.p. It is suspended at its upper end from the derrick and is
strapped back to the
derrick when not in use. Downward thrust is applied by the derrick
operating under hydraulic pressure, and by control of the derrick
position the angle
of boring can be determined, e.g. when setting stay anchorages.
A fibre-glass boom-extension and personnel bucket can be fitted to
the derrick for lifting men aloft, e.g. for tree cutting,
aerial-cable maintenance or work on decayed poles. If a personnel
bucket is fitted, the hydraulic controls may be extended to the
bucket if required, and under these conditions a hydraulic power
supply is available on the bucket fox operating tools. The whole of
the bucket system is insulated to guard against accidents due to
contact with power wires.
The derrick can be used for a variety of operations, including
loading and unloading the vehicle itself, loading and unloading
poles on and from pole stacks and
stores-carrying vehicles, setting or recovering poles, supporting
decayed poles, lifting personnel and steering the pole-hole borer.
When not in use, the boom extension is retracted and the derrick
stows diagonally across the vehicle body.
At the rear of the vehicle a hydraulic power take-off is provided
for operating auxiliaries such as an earth-punner or a 25-ton
A control panel is fitted at the rear of the vehicle so that the
operator has a clear view of all the functions. Controls are
provided for extending and retracting the stinger, lifting and
lowering the boom, rotating the derrick, operating the borer, and
controlling the stabilizers, hydraulic power take-off and governed
engine speed. The last may be varied according to the power
requirements of the operation being performed and is increased or
reduced in steps by flicking a switch up or down.