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A NEW MOBILE CRANE.

12th December 1922
Page 10
Page 10, 12th December 1922 — A NEW MOBILE CRANE.
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A Battery-propelled Vehicle, which is Constructed to Lift and Transport Loads of 15 cwt. Four Motors are Included in its Design to Effect the Operations of Travelling, Lifting, Lowering, Revolving and Luffing.

rrEIE _MOBILE crane now fills a dis tinct sphere of4utility in railway and dock sheds, warehouses, and the like, and enables operations which. were at one time laborious and costly to he conducted with economy and expedition. This class of equipment is also of considerable value in connection with loading and unloading of motor lorries, and unquestionably facilitates the execution of such duties where the loads which have to be dealt with are heavy and unwieldy.

Those who have recourse to this class of equipment—and there must be many classes of commercial-vehicle users among their ranks—will undoubtedly find much of interest in the new 15 cwt., four-motor, electrie-battery crane which has recently been designed and built by John H. Wilson and Co., Ltd., of Dock Road, Birkenhead_

In general, the crane is of the mobile, jib type, mounted on a. carriage having solid-rubber-tyred wheels, and it has been specially designed for handling loads on goods platforms. It is built to lift 15 cwt. at 10 ft. radius, and 10 cwt. at, 12i ft. radius. The motions of lifting and lowering, luffing, revolving and travelling are all electrically carried out. The electrical equipment is suitable for 40 volts direct current, and comprises one lifting motor, one revolving and luffing motor, and two travelling motors, all of them being of 4 b.h.p. at 750

r.p.m. The motors, which are of the series-wound reversing type' are totally enclosed and are made by Laurence Scott and Co., Ltd. They are capable of giving a full load output for half an hour with a temperature rise not ex1126

ceeding 90 degrees F., a solenoid brake being fitted Ix the lifting motor.

The controllers, which are the product of Messrs. Allen West, are of the drumreversing type, and are operated by crank handles in the case of the lifting, revolving, and luffing operations, the controller for travelling being operated by a pedal, which is interlocked with the travelling brake levers, in order to release the brake on starting the motors.

The resistances are self-contained in controllers in the case of travelling and revolving, but separately mounted in the case of the hoistinrcontrol. The storage batteries are of the Ironclad-Lxide type made by the Chloride Electrical Storage Co., Ltd.. and they are placed fore and aft in the crane carriage. The batteries are capable of providing power for lifting 1.5 cwt. a height of 10 ft. at a speed of 30 ft. per minute, and at a rate of 40 times an hour for five hours, quite apart from the necessary operations of revolving, luffing and travelling. The capacity of the batteries is 258 amp. haurs. A suitable charging socket, as well as a charge and discharge meter, is provided, and all exposed wires are run in metal conduits.

So far as the lifting gear is concerned, the gearing is arranged in doublepurchase and has machine-cut teeth. The barrel is 7 ins, in diameter and is grooved to take wire rope, the load being lifted on two falls of rope made of extra plough-steel wire of Fin. diameter. The barrel will hold sofficienterope for a lift of 20 ft., and an overwied'and overload switch is provided.

The revolving gearing consists of a rack, with machine-moulded teeth, bolted to the carriage, and a suitable rack-pinion and machine-cut worm-gear, on the revolving structure. A claw clutch is arranged for changing over the motor for the operation of luffing. A foot brake is fitted to the revolving gear. Referring to the luffing gear of the crane, the jib is capable of being adjusted, with the full load suspended, by means of a vertical screw, which is operated through bevel gearing from the same motor which effects the revolving motion.

The travelling operations of the crane are effected by two separate chain and worm-gear drives. The front wheels are arranged to swivel far easy steering purposes. The steering gear is operated from the driver's platform on the revolving structure, and a foot-released brake controlling both motors is fitted, the brake being normally in the " on " position. Both front and rear axles are fitted with springs, and the tyres are 32 ins. in diameter by 5 ins. wide.

The parts of the carriage and revolving superstructure are made of steel sections, plates and angles, the revolving platform being made of cast-iron covered with timber. The carriage is provided with a strong centre casting to take a forged-steel centre post. The revolving structure is supported.on a strong pivot casting, which is securely bolted to the undercarriage and is provided with ballthrust washers. All the principal bearings throughout the mobile crane are bushed with gunmetal, suitable prevision being made for lubrication.

So far as the principal dimensions are concerned, the width of the carriage of the mobile crane is 6 ft. overall, other particulars being as follow :—Tail radius of revolving structure, 3 ft. ; wheelbase, 6 ft. ; height to jib head at 10ft. radius, 17 ft. 3 ins.; height to jib head at 12L-ft. radius, 12 ft. 6 ins. ; weight of crane in working order, 5 tons. The crane 1E4 made to pass under a height of Ilift.

With regard to the capacity of the Wilson mobile crane, it is capable of lifting a full load at a speed of 30 ft. per minute, of travelling at 3-1--4 m.p.h. with a full load, and of revolving at 4 m.p.h. with a full load. Jahn H. Wilson and Co., Ltd., are specialists in the manufacture of cranes and similar equipment, and that they possess a thorough understanding of the requirements of users of this class of equipment, is indicated by the vehicle which we have briefly described.

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