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DEMONSTRATING A MOBILE BATTERY CRANE.

13th February 1923
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Page 23, 13th February 1923 — DEMONSTRATING A MOBILE BATTERY CRANE.
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The Ransomes' Runabout Crane Has Been Entirely Redesigned and Embodies Many Unique Features.

wE HAVE on many occasions pointed out the need for expedit.• big the loading and unloading of motor vehicles utilized for carrying goods. It is, of course, equally necessary to perform. these operations rapidly in the case of other means of transport which are often used in conjunction with road vehicles, thus railway tracks are often loaded from lorries or unloaded into them, and the same applies to ships.

In performing such work one of the most necessary "machines to employ is a mobile crane. Until recently such cranes were cumbersome, and their mobility often confined to a -set of rails.

In the Ransomes' electric truck crane, of which the -chassis is made by Ransomes, Sims and Jefferies, Ltd.. and the crane portion by Ransomes and Rapier, Ltd., the chassis is so built that it fauns -in itself the turntable for the jib. It is provided with two pairs of swivelling wheels, and two pairs which do not swivel. Each pair forms a. un:t; thus those 011 the front and rear do the steering, whilst of the side wheels the outer one of each pair is driven, and the inner one runs free.

In each unit, formed of driving wheel and free wheel, these are mounted on a short axle which pivots on a bracket supported by the frame, so that the -wheels can adjust themselves vertically when travelling-over uneven ground. In the previous design the driving heels were mounted on a continuous axle, with the result that they were sometimes lifted off the ground when passing over inequalities.

Each outer wheel is separately driven, through a double-reduction gear, by an • electric motor supported on a rubber buffer, which takes the weight and the torque, and i5so sufficiently elastic that the whole motor win lift slightly with the wheel when necessary. The final drive is by totally enclosed bevel gearing.

The front end of the armature shaft in each motor is extended and carries a small brake drum with a band-type shoe.

When travelling backwards and forwards in the ordinary manner, steering is effected by the small wheel units at the front and rear, and the driving motors run forward or are reversed togetherWhen it is required to turn the crane round on its awn centre, or, in other words, to slew the jib, the steering wheels are locked round until they are at right angles to' the driving 11 wheels.

The steering gear is Connected with a special .indioating. controller or contactor gear, and directly the steering wheels are brought round to the right-angle position, the contactor gear causes the motors to rotate in opposite directions so

soon as the power is switched on, and the chassis them turns exactly on its own centre, as if it were mounted on a ver tical spindle..

The front and rear wheels are each provided with two spiral springs, and

both, when running or lifting a load, these springs act. as buffers, which relieve the whole machine from shock.

The controller for hoisting or derrick, ing is situated to the right of the driver's seat, the operating lever is positioned in a gate; the movementof the lever on one side of the gate hoists or lowers the load, and on the other side raises or lowers the jib, according to whether the lever be moved backwards or forwards. The loads may also be lowered by gravity under perfect control, and thus conserve current.

Close behind the driver is, the single motor, which rotates the respective rope barrels through the medium of worm and spur gearing.

Embodied in the drive is an arrangement of Ferodo-faced cone clutches and brakes, so designed that the brake by which the load is secured in any desired position, is progressively released as the clutch is applied, the reverse holding good when it is desired to arrest the suction. At the same time the motor is automatically started or stopped as required, thereby conserving electrical energy.

The accumulators are contained in two easily detachable boxes situated upon the rear portion of the chassis, so that they serve the purpose of counterbalance weights.

The crane is made in three sizes, to deaf with loads of 74 cwt., 15 cwt. and 20 cwt. respectively. Each size is also made in two types—the "L " for passing under doorways approximately 7 ft. 6 ins. high, and the "II " for passing under door ways approximately 10 ft. high. All sizes and types will pass through a gangway having a clear width of 5 ft. 4 ins., and will rotate in a circle 7 ft. 6 ins, in diameter. They are adapted to operate successfully and to run on moderately uneven ground, and will surmount or operate on gradients up to one-in-ten, whilst the pressure on any wheel never exceeds three-quarters of a ton. Each mem is provided with an Ironclad Exide battery, consisting of 20 cells having a capacity, on the five-hours' rating, of 258 ampere-hours; alternatively, the battery may consist of 40 cells giving 129 ampere-hours. The capabilities of the latest machine must be seen to be believed, and it Was with this object in view that the builders recently invited a number of Press representatives to attend a series of demonstrations which was held in their works and along the neiahbanring dockside.

The first demonstration -was to show the manireuvra,bility of the machine. In this respect it is really a most remarkable contrivance, almost human in the way it answers to its controls. #or the second demonstration the crane lifted large logs, weighing 15 cwt. each, from a timber rolley and piled them on to a timber stack. Te do this work not only had it to lift and swileg round the logs, but the whole machine had to travel backwards and forwards, and the •seed at which it performed the combined operation showed that it can handle materials far more rapidly than could be done in any other manlier: Irater the crane was shown lifting castiron bedplates on to a Stirk planing machine, and also lifting a „crankshaft, weighing approximately 15 cwt., from a Ransome Type C industrial truck into position between the centres of a lathe. The accurate manner in which this heavy crankshaft was lifted or lowered a quarter of an inch at a time was simply astounding. Proceeding from the engine works, the crane travelled for about a quarter of a mile along a, dockside laid with rails, which in some places projected considerably above the ground. These rails and other obstacles the crane surmounted with the greatest ease. The last trial was that of lifting cases, weighing 121 cwt. each, from a Ransome lorry into a railway truck, a task which was performed with ease.

All the visitors were greatly impressed with the wonderful capabilities of this simple but remarkably efficient machine, and there is no doubt in our mind that the Ransomes' crane has before it a wonderful future, and will certainly meet a long-felt want. Its price complete with batteries is 2850 for the I.5-cwt. model.

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