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1907 Commercial Motor Show

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Review from Motor Car Journal


The first International Commercial Motor Vehicle and Motor Boat Exhibition at Olympia, W., was opened on Thursday, last week, by Sir Wm. Treloar, Lord Mayor of London.

Although the building is by no cleans crowded with exhibits, an interesting collection of motor-'buses and industrial vehicles has been got together.

Dealing first with steam wagons, it may be mentioned that Messrs. D. Stewart and Co., Ltd., Glasgow, show a 5-ton machine on the Stewart-Thornycroft system, Mann's Patent Steam Cart and Wagon Company, Ltd., Leeds, a 2-ton wagon with locomotive boiler, for Messrs. Tangyes, of Birmingham, Messrs. Robey and Co., Ltd., Lincoln, a 5-ton gear driven lorry, Messrs. James Ellis and Co., Ltd., a 2-ton and a 6-ton steam wagon, and Messrs. Straker and Squire, Ltd., a 5-ton lorry with locomotive boiler.

The St. Pancras Ironwork Company, Ltd., are present with one of their 5-ton steam wagons with special fire tube boiler and patent rocking fore-carriage.

Included in the exhibit of the Lancashire Steam Motor Company, Ltd., Leyland, is a Leyland five-ton steam lorry, of which a large number are in use in different parts of the country, especially in Lancashire.

A couple of the well-known Foden 5-ton wagons are displayed by Messrs. Fodens, Sandbach, one being intended for Messrs. J. and H. Robinson, Ltd., Greenwich.

Considerable improvements have been effected in the Yorkshire steam wagon, that now exhibited by the Yorkshire Steam Wagon Company, Ltd., having enclosed vertical compound engines and chain transmission.

Messrs. Alley and MacLellan, Ltd., Glasgow, through their London agents, Messrs. E. W. Rudd and Co., exhibit two of the Sentinel steam wagons, and also a number of the component parts of the same.

In addition to one of their tractors, Messrs. Wallis and Steevens, Ltd., Basingstoke, show a Wallis steam wagon.

Steam tractors are shown by Messrs. Tasker and Sons, Andover, Messrs. Wm. Foster and Co., Lincoln, and Messrs. Robey and Co., Ltd., Lincoln.

One of the largest exhibits of petrol motor-'buses is that of the Milnes-Daimler Company; three of the latest 28 h.p. German-Daimler chassis fitted with different types of bodies are on view, including a thirty-seated gallery char-a-banc for the Great Western Railway Company.

Captain Theo. Masui presents the latest type of 24 h.p. Germain 'bus chassis, in which the engine is arranged under a bonnet instead of under the driver's seat as was the case in the earlier models.

A number of improvements are to be found in the latest 35-40 h.p. Critchley-Norris bus chassis shown by the Critchley-Norris Motor Company; the clutch, which is of the leather-faced cone type, is fitted with an eccentric motion which enables it to be withdrawn with a minimum of exertion; special attention has also been paid to the lubrication and to the brakes.

The Neue Automobil Gesellschaft, Berlin, exhibit a 24-26 h.p. double-deck 'bus and a 16-18 h.p. street-watering wagon, the latter having been built for service in Berlin.

The exhibit of the Wolseley Tool and Motor Car Company, Ltd., comprises a 30 h.p. 'bus chassis, a 30 h.p. 33-seated char-a-banc with canopy, an 18 h.p. ambulance with Elastes tyres, and a new 10 h.p. taxameter cab.

Messrs. Durham, Churchill and Co., Sheffield, who are meeting with considerable success with their heavy petrol vehicles, show a 24-30 h.p. Churchill 26-seated char-a-banc, fitted with Aster four-cylinder engine and the Champion change-speed gear, the pinions of which are always in mesh. They also exhibit an 18-22 h.p. chassis, suitable for use as a 2-ton lorry or van, or as a single-deck 'bus.

Fiat Motors Ltd., show one of the latest Fiat 40 h.p. 'bus chassis with the engine under a bonnet, and a 40 h.p. 5-ton lorry built for the Soudan Government.

Commercial Cars, Ltd., Luton, make their debut with a 30-seated char-a-banc or "country coach," the feature of the chassis being the change-speed gear. The pairs of pinions of the latter are always in mesh, the desired pair being made to transmit the power by means of dog clutches.

The Lancashire Steam Motor Co., Ltd., exhibit a 35-40 h.p. double-deck petrol 'bus for the London Central Motor 'Bus Company, and a 31-seated char-a-banc fitted with a 50 h.p. four-cylinder engine.

Another excellent example of a British-built motor- 'bus is to be seen in that exhibited by the Maudslay Motor Co., Ltd. It is fitted with a 35-45 h.p. engine and the White and Poppe automatic carburettor, and throughout bears evidence of careful design and construction.

Messrs. Dennis Bros., Ltd., have a very interesting exhibit. Of the buses, reference may be made to a 40 h.p. vehicle with Aster engine and the Dennis worm drive, built for the London Road Car Company. The firm are also paying special attention to heavy petrol lorries and vans and show a 40 h.p. brewers' lorry for Messrs. Wm. Hancock and Co., Cardiff, and a 20 h.p. two to two and a half ton van for Messrs. Carter Paterson and Co.

The Ryknield Motor Company, Ltd., of Burton-on-Trent, who are now devoting special attention to motor-'bus work, show a 40 h.p. chassis in which a number of special points are comprised, notably the single lever control of the throttle and the ignition, and the patent triangular under-frame, which prevents the pinions on the ends of the differential shaft, which drive gear rings bolted to the rear road wheels, getting out of alignment. Other points worthy of notice are the large radiator and the adjustable steering gear.

A new range of Swiss-built machines is to be seen at the stand of Verna Motors, Ltd.; three models are staged, 16-18 h.p., 20-24 h.p., and 30-35 h.p.; the chassis of the latter is suitable for use as a lorry or as a motor-'bus. The four-cylinder engines have low-tension ignition while the transmission is by a cardan shaft and bevel gear to a live axle.

The Turgan commercial vehicles are displayed by the Cannstatt Automobile Supply Association; they comprise a 12 h.p. chain-driven chassis suitable for a 15 cwt. van, a 24 h.p. 3-ton tip wagon, and a 30-40 h.p. 'bus chassis.

Other exhibitors of motor-buses include the Beaufort Motor Company, Ltd., Messrs. J. E. Hutton, Ltd. (Berliet), the New Arrol-Johnston Co., Ltd., Messrs. J. and E. Hall (the Saurer system), Mors, England, Ltd., the Thames Engineering Company, Ltd., the British Automobile Development Company (Brush), the Motor Car Emporium, Ltd (Durkopp and De Dion), Messrs. Scott, Stirling and Co., Ltd., Messrs. Straker and Squire, Ltd.

Bodies for motor-'buses and delivery vans are shown by Christopher Dodson, Ltd., Westminster, and Messrs. J. Liversidge and Son, Ltd.

The Darracq-Serpollet Omnibus Company, Ltd., show several models of the Darracq-Serpollet steam chassis of 20-25 h.p. and 30-40 h.p. suitable for delivery vans and motor-'buses. An interesting exhibit is the 30-40 h.p. demonstration vehicle built for the Emigration Dept. of the Canadian Government, of which an illustration is given elsewhere.

Much interest is centred on the stand of the Daimler Motor Company, Ltd., where is shown a complete Renard road train consisting of a locomotor, two passenger coaches and a luggage van.

New combination petrol-electric motor chassis, suitable for motor-'buses and delivery vans, are displayed by Messrs. Greenwood and Batley Ltd., Leeds, Messrs. Straker and Squire, Ltd., and Messrs. W. A. Stevens, Ltd., Maidstone.

In the Greenwood and Batley vehicle in 35 h.p. four-cylinder engine drives a continuous current dynamo. In the rear of the latter are two series wound motors, each driving through distinct enclosed counter-shafts and worm gearing one half of the rear live axle.

In the Straker-Squire 'bus the engine, which is of 30 h.p., is coupled direct to a dynamo which generates energy at varying amperage and voltage, this being utilised to operate two electric motors geared to a countershaft, whence the power is transmitted to the rear road wheals by silent chains.

In the Stevens system the engine is directly coupled up to a special dynamo which has two windings so arranged that they can be coupled up either in series or in parallel. In line with the dynamo is the electric motor which drives the rear axle through a cardan shaft and bevel gear. The principal feature is found in the controller, which is so coupled up with a pedal that its position cannot be changed unless the pedal is depressed, which breaks the circuit as well as slowing down the speed of the engine by acting on the throttle, which latter is also controlled by a lever on the steering wheel. We hope to refer to the Stevens system more fully in a later issue.

Passing now to heavy patrol commercial vehicles, the well-known Orion lorries are being kept well to the front by Messrs. Moss and Woodd, who are showing a standard 3-ton wagon fitted with 20 h.p. horizontal double-cylinder engine.

In addition to a Decauville van and lorry, Messrs. H. M. Hobson, Ltd., show a 30 h.p. Hobson heavy lorry fitted with the Jenatzy patent suspension. The invention consists mainly in mounting the mechanical part of the vehicle as a whole upon a second frame, entirely independent of the vehicle frame, and suspended from the latter by special springs, so that the absorption of vibrations and shocks no longer depends upon the load which tire vehicle is carrying.

Messrs. Argylls, Ltd., and Argylls London, Ltd., exhibit a new 16-20 h.p. 30-cwt. lorry chassis with the engine located under the driver's seat and a worm drive in place of the usual bevel gear, several light vans, a newspaper delivery van as built for the "Glasgow Evening News," a 10-12 h.p. sample carrier, and an Argyll 14-16 h.p. standard cab.

A novelty is seen at the stand of the Enfield Autocar Company, Ltd., in a 50 h.p. vehicle specially designed for the conveyance of horses.

The Simms Manufacturing Company, Ltd., exhibit is number of commercial vehicles ranging from a nest 20 cwt. van to a 28-35 h.p. 5-ton lorry built for the Great Central Railway.

Heavy petrol vans and lorries are also displayed by Messrs. James and Browne, Ltd., the new Arrol Johnston Car Company, Ltd., Commercial Cars, Ltd., Luton, Messrs. Scott, Stirling and Co., Ltd., Halley's Industrial Motors, Ltd., Glasgow, and Messrs. Straker and Squire, Ltd.

Light petrol motor delivery vans for loads of from 7 to 30 cwt. are exhibited by the Lindsay Motor Manufacturing Company, Ltd.; the Horley Motor Company, Horley; Sturmey Motors, Ltd., Coventry; Belsize Motors, Ltd., Manchester; Messrs. Glover Bros., Ltd.; Messrs. Mors England, Ltd.; Messrs. West, Ltd.; Messrs. De Dion-Bouton, Ltd.; Messrs. Alldays and Onions; the Adams Manufacturing Company, Ltd.; the Lancaster Motor Garage; Messrs. W. T. Clifford Earp, Ltd.; and Messrs. J. A. Lawton and Co.

The Star Engineering Company, Ltd., Wolverhampton, have on view a neat 14 h.p. van for loads up to 15 cwt.; a Star 10 h.p. four-cylinder landaulet and a 25 cwt. van were also expected.

A novelty is seen in the new vehicles - a 15 cwt. delivery van, a hansom cab, and a six-seated cab — shown by the Pullcar Motor Company, Ltd., Preston. The engine and driving gear are so connected with the front pair of road wheels as to form a two-wheel tractor or ‘avant train’ which can be applied to ordinary carriage bodies. An illustrated notice of the system W. given in the M.C.J. of July 28th last.

Two useful petrol motor delivery vans are shown by the Industrial Motor Company, Windsor. The 9 h.p. vehicle has a capacity of 10 cwt., while the 12 h.p. machine is intended to convey loads up to 20 cwt. at a speed of twelve miles per hour.

A novelty to this country is the 14-16 h.p. petrol delivery van exhibited by Messrs. Jesse Ellis and Co. it being fitted with the Fouillaron variable speed gear obtained by expanding and contracting pulleys; the system was described in connection with our report of the recent Paris Salon.

The Motor Engine and Manufacturing Company, Ltd, show a couple of chassis suitable for delivery vans, the feature lying in the engine, which is of the Duplex two stroke type, of which an illustration was given in these pages two or three months ago.

The Lacre Motor Car Company, Ltd., make a feature of the Lacre 16 h.p. vans, the chassis of which are built by the Albion Motor Car Company, Ltd. Interest in the display is increased by the presence of the first chassis of the kind in England, which has covered a distance of close on 30,000 miles and is still in excellent running order.

A novel and useful tradesmen's carrier is exhibited by the Autocar and Accessories Company, Ltd., of South Norwood; it is a three-wheeled machine fitted with a 5 h.p. air-cooled engine, and is capable of carrying loads up to about 4 cwt.

Messrs. Mann and Overtons, Ltd., exhibit a 10-12 h.p. Unic motor-cab, similar to those which are now largely being used in London.

Messrs. West, Ltd., show a 10-12 h.p. West-Aster with single landaulet body, specially designed for public service.

Other exhibitors of motor-cabs include the Adams Manufacturing Co., Ltd.

New Leader Motors, Ltd., Nottingham, are present with a new 10-12 h.p. four-cylinder cab, the engine of which is placed near the driver's seat somewhat as in the Lanchester, the usual bonnet being thus dispensed with. A useful 10-12 h.p. 10-cwt. van is also on view.

Messrs. Barford and Perkins, Peterborough, show two sizes of their petrol motor rollers, while Messrs. Ransomes, Simms and Jeffries, Ltd., Ipswich, in addition to a range of their well-known motor lawn mowers, exhibit a series of the Orwell petrol engines from 2.75 h.p. to 12 h.p. they are now turning out.

As regards electrical vehicles, the Electromobile Company, Ltd., exhibit a motor ambulance built for the City of London Corporation and a 15-cwt. delivery van.

The Electric Van, Wagon and Omnibus Co., Ltd., in addition to the Electrobus, show a 5-cwt. delivery van and a 20-cwt. covered wagon.

Messrs. Drummond Bros., Ltd., have an interesting display of their special lathes for the repair of motors, as well as a small bench shaping machine, and an assortment of lathe chocks and accessories.

Other exhibitors of machine tools include Messrs. Ludwig Loewe and Co., Messrs. Selig, Sonnenthal and Co., Messrs. Richard Melhuish, Ltd., Messrs. Burton, Griffiths and Co., and Messrs. Alfred Herbert, Ltd., Coventry.

The Kirkstall Forge Company exhibit steel frames for motor-'buses and delivery vans, and also draw attention to their special axles and hubs, made in accordance with the Butler patents.

A new paraffin carburettor known as the Cottrell is shown by Paraffin Carburettors, Ltd., Birmingham. The device, which is provided with a two-way cock, so that the engine, when first put into operation, may be started on petrol, comprises a special form of expanding and contracting choke tube around the spraying nozzle. The fuel is first partly vaporised and mixed with air, the mixture being afterward heated ere passing into the explosion chambers by means of the exhaust gases which, before passing away, are circulated round the inlet pipe.

Good types of motorists' raiment are exhibited by Messrs. H. J. Nicoll and Co., Ltd whose rainproof frieze motor coats are well known, and by Messrs. Samuel Bros.

Messrs. A. W. Gamage, Ltd., have their usual comprehensive selection of clothing and accessories, the latter including horns, accumulators, speed indicators, &c., as well as tools, lamps and syrens.

Artillery wheels and bent timber for motor bodies constitute the display of Messrs. Smith, Parfrey and Co., who also show the Clincher "Grid" rubber tyre.

Tangent Wheels, Ltd., have also a large assortment of their specialities.

The Stern-Sonneborn Oil Company have a complete selection of their oils; the Fieldine lubricating oils and varnishes are on the stand of Messrs. J. C. and J. Field, Ltd.; varnishes and paints constitute the display of Messrs. Docker Bros. Ltd., and Price's Patent Candle Company, Ltd., are represented by their lubricants for care gear-boxes and chains as well as preservatives for leather-faced clutches and the like.

The "Shell" motor spirit is kept before the notice of motorists by the General Petroleum Company, Ltd.; and the Anglo-American Oil Company, Ltd., have samples of motor spirits and oils for heavy vehicles; the Vacuum Oil Company have their familiar assortment of lubricating oils and greases.

Messrs. Brampton Bros., Ltd., have a selection of driving chains and sprockets for commercial vehicles.

The most attractive exhibition of the chain makers at this show, however, is that made by Messrs. Hans Renold, Ltd., who show their roller and silent chains in motion. The latter type is now being largely employed in London 'bus work to the satisfaction of police authorities and engineers alike.

The Coventry Chain Company, Ltd., keeps its productions to the fore, showing a selection of chains and chain wheels for commercial vehicles.

Miscellaneous tools and accessories are on view on the stand of the American Importing Company, who show the "Auto Cie " — a handy combination for cars or garages.

Messrs. Ross, Courtney and Co., Ltd., have a varied exhibit of their lubricators, oil pumps, motor tyre pumps, the Ross Courtney valve and other specialities.

The Fastnut washer, recently illustrated in our columns, is exhibited by Messrs. Fastnut, Ltd.

The "New Era" petrol fire extinguisher is shown by the Valor Company, Ltd.

Messrs. Brown and Barlow, Ltd., exhibit their carburettors, and Messrs. Salsbury and Son, Ltd., have a representative collection of the "Salsbury Dietz" lamps and other high grade productions for lighting the way of heavy automobiles.

Messrs. W. H. Willcox and Co., Ltd., have a collection of their pumps, lubricators, jacks, gauges, &c., as well as head lamps and lubricants for motor lorries.

Tyres are a fairly comprehensive section of the show, their, leading specialities being shown by the Swinehart Tyre and Rubber Company; Messrs. J. Liversidge and Son, Ltd. (the "De Nevers" tyre for commercial vehicles); the Shrewsbury and Challiner Tyre Company, Ltd.; the Peter Union Tyre Company (who show a number of tyres that have done long service); the Gaulois Tyres, Ltd.; the Dunlop Rubber Company, Ltd.; and the Sirdar Rubber Company, Ltd.

Non-skids. naturally constitute the feature of the display made by the Parsons Non-skid Company, Ltd., whose Grippa non-skids and Sparklet inflators are well known.

The adjoining stand is occupied by Messrs. Harvey Frost and Co., Ltd., who are constantly introducing new features in their appliances.

The New Motor and General Rubber Company, Ltd., make a bold display of their "Rub-metal" non-skids and draw attention to their facilities for tyre repair work generally.

In addition to their usual show of speedometers, mileage recorders, watches, etc., Messrs. S. Smith and Son, Ltd., have a new taximeter.

The Cowey patent extension speed indicator fitted with a dial for the dashboard and another for the convenience of the passengers is exhibited by the Cowey Engineering Company.

Electrical specialities of wide range are on the stands of Messrs. Peto and Radford, Ltd., and also of Marconi's Wireless Telegraph Company, Ltd.

The Doherty Motor Components, Ltd., have their usual display of components and fittings, including radiators, lubricators, bonnets, &c., for heavy vehicles, motor-'buses, &c.

Machine cut gears are shown by Messrs. David Brown and Sons, Ltd.

Messrs. John Marsden, Ltd., make a special display of radiators for motor-'buses.

The Bentall motor is on the stand of Messrs. E. H. Bentall and Co.

The Car and General Insurance Corporation, Ltd., take advantage of the occasion to make known their facilities for insurances to meet the requirements of recent legislation.

Review from The Engineer


The first International Exhibition of Commercial Motor Vehicles and Motor Boats, hold under the auspices of the Society of Motor Manufacturers and Traders (SMMT), was opened at Olympia on Thursday, March 7th, and will remain open till to-morrow — Saturday. It will be remembered that this Society last year decided, on account of the great demand for space at its previous exhibitions, to divide the commercial and pleasure sides of automobilism and give to each its own show. The decision was wise, and we think, on the whole, has been justified by the success of the separate exhibitions. At Olympia there are nearly 250 exhibitors, including most of the builders of the latest types of vehicles and the best known systems of power generation, with one or two notable exceptions. There are heavy steam wagons, steam and petrol omnibuses, light electric cars, and commercial travellers' sample carriers.

Quite a feature of the show is formed by the several exhibits of combined petrol-electric systems, of which much has been heard recently. It is noteworthy that in each of these cases continuous current apparatus is used.

The motor omnibus chassis shown by Messrs. Greenwood and Batley has a 35 horse-power petrol motor coupled direct to an electric generator supplying continuous current to a double armature electric motor, and the latter drives a live rear axle by worm gearing without necessitating the employment of differential gear. The speed of the vehicle is regulated by an electric controller using no external resistance, and as there is no mechanical connection from the engine to the road wheels, no clutch is necessary. About the engine there are no special features. The generator is of the protected four-pole compound wound type, and is connected to the engine crank shaft by a short flexible coupling, a precaution necessary to compensate any distortion of the frame. The commutator is at the front end, directly beneath the floor boards, and the rear end of the casing is open to keep the generator cool. The motor is of the protected four-pole series wound pattern, having two distinct armatures within the same yoke. It is carried on trunnions, and connected to the rear live axle by a large central radius tube, so that although the weight of the motor is carried on the frame of the omnibus, it is free to swivel about its transverse and longitudinal axes. This arrangement allows of the perfect alignment of the armatures and worm shafts. The propeller shafts between the armatures and worm shafts have flexible couplings, and the whole is encased in sheet steel tubes. There are two separate worm gears driven by the two armatures, and the worms run below their pinions, and so are always well lubricated. The worm wheels are of manganese bronze bolted to flanges on internal driving shafts which have jaw couplings engaging direct with the road wheels. The electric controller is operated by a handle below the steering wheel, and drives four forward speeds and a reverse. Although placed below the floor boards at the foot of the steering column, it is easy of access. The method of control is a combination of series parallel and field, giving a wide range of speed. The series speeds, which are the two lowest, give a suitable differential action, while it is claimed that when the controller is in parallel a torque is produced inversely proportional to the speed of each road wheel. The engine is controlled by the usual ignition and throttle lovers on the steering wheel, supplemented by a single pedal. A slight movement of the pedal throttles the supply of gas, and breaks the electrical circuit before the brakes are applied. The system, however, does not provide electric brakes, while it adds materially to the weight of the vehicle, the chassis shown at Olympia weighing, we are informed, 3 tons 10 cwt. The generator accounts for 6 cwt., and the motor somewhat less. The brushes are arranged at 45 deg.

Another petrol electric system is shown by the firm of W. A. Stevens, Limited, Maidstone. In this case the continuous current dynamo has a compound wound armature, with two commutators, and generates constant watts, the voltage varying inversely with the amperage demanded by the electric motor. It is ventilated by means of a fan at the end farthest from the engine. The leads from, the dynamo arc carried through variable resistance switches to the controller, and thence to a series wound motor. The latter drives the live roar axle by means of a cardan shaft and gearing. The petrol engine drives the dynamo through a flexible coupling. A special form of controller is a feature of this system. It is designed for two forward speeds and a reverse, and is of the dual pattern, with the bars arranged in two concentric circles mounted on an insulating base. Four insulated metallic brushes, supported by the four arms of the switch carrier, serve to connect the various segments of the inner and outer circles. The control of the vehicle is effected partly electrically and partly mechanically, as will be gathered from the accompanying diagrams, Figs. 1 and 2, in which B B is the dynamo armature winding; E, motor armature; F, motor field windings; G G,, variable resistances; H H1, resistance switches; I, foot pedal; J, connecting-rod; K, change speed lever; L, catch plate; A, solenoid; D, plunger; 0, locking arm; P, throttle; q r s t, insulated metallic brushes; U, four-armed switch carrier; V, centre pin; W, control lever spring; X, foot pedal spring; Y, locking nut to throttle; Z, governor control lever; 1 2 8 4 5 6, dynamo circuits contact bars; 7 8 9 11 18, motor circuit contact bars; 10 12, dead bars. The solenoid A is excited by a shunt circuit from the dynamo terminals, the tendency of the plunger D to close the throttle P increasing with the dynamo voltage. This action of the solenoid is opposed by the spring W, the tension of which can be varied by the governor control lever Z on the steering column, so that with the increased tension of the spring a greater electromotive force will be required from the dynamo to enable the solenoid to close the throttle. So long as the volts generated by the dynamo are not sufficient to overcome the tension of the spring W, the throttle will remain wide open and the engine will run at its full speed. With the rise of voltage due to the reduction of the demand of the electric motor for current, the pull of the solenoid will overcome the tension of the spring and close the throttle. On the foot pedal being depressed, tension is put on the spring X, acting in the same direction as the solenoid, effecting thereby the regulation of the governing electromotive force, and, in consequence, the engine speed. It should be mentioned that the throttle is prevented from entirely closing and stopping the engine by the adjustable locking-nut Y. The engine being started, the dynamo excites, but as no amperes are demanded by the motor, and the dynamo is wound to give constant watts at varying voltages, the electromotive force rises to 100 volts at a very low speed, at which speed the engine governor comes into action. On putting on the electrical load the volts fall on the increase of current demanded, and the throttle opens immediately as a result. The speed of the engine will thus vary with the power required by the car, but not necessarily with the car speed. The speed of the vehicle is governed from either the steering column or the foot pedal. It is claimed that in the Stevens system the combined efficiency of the dynamo and motor at all ordinary speeds exceeds 72 per cent.

Amongst the vehicles propelled direct by internal combustion engines there are some highly interesting exhibits, and the mechanical and constructional features indicate the marked progress which the designers of the petrol motor omnibus have made in the last twelve months.

The omnibus chassis exhibited by Milnes-Daimler, Limited, must be alluded to as an example of good design and high-class workmanship; and the motor omnibus shown by the Ryknield Motor Company has several good features, including a 40 horse-power four-cylinder engine (5.125in. by 6in.), and a single-lever control. In the latter, by the movement of a lever mounted in the centre of the steering wheel, both the throttle and the advance spark mechanism can be altered to give any combination of positions, such as throttle open and spark advanced, or throttle opened and spark retarded, and so on. There is also an adjustable steering pillar, by which wear of the screw can be taken up. The improved feature consists of a divided steering nut working on a triple-threaded screw. The two halves of the nut can be forced apart by means of an adjusting screw, so that they grip the thread at top and bottom respectively. A triangular under-frame and spring drive arrangement prevent the driving pinions being thrown out of alignment with the gear rings on the road wheels, as might otherwise be caused by springing and twisting of the main frame. Positive and automatic lubrication of the engine bearings is provided, oil being forced by a pump mounted in a well at the bottom of the crank chamber through sight feeds on the dashboard direct to the bearings, whence it drains through a filter back into the oil well.

An omnibus constructed by this company has been running very successfully for some time in London with a petrol consumption of 6.75 miles per gallon, and a consumption of lubricating oil equal to 1 gallon per 218 miles. The engine has no governor, the speed being controlled by an automatic valve in the mixture pipe.

The Hallford motor omnibus chassis built by Messrs. J. and E. Hall, Limited, Dartford, under the Saurer patents, is one of the most interesting and instructive vehicles shown. One of the chief characteristics of this exhibit is the method of converting the engine into an air-brake — a commendable feature. The method on which this apparatus acts will be understood by referring to the diagram, Fig. 3. The fundamental principle consists in the regulation of the periods of opening of the exhaust valves in relation to the angular position of the crank shaft, while cutting off at the same time the admission of gas, and giving the air a free passage through the carburetter. At the lower end of the steering column is a double spiral cam, which is rotated by a steel spindle contained within the steering column, its motion being controlled by the lever on top of the wheel. In the grooves forming the two ends of the spiral cam are rollers, which actuate two independent levers. The upper of these levers is connected directly with the throttle valve, and the lower one converts the engine into an air compressor in the following manner:— The exhaust cam shaft E C is driven from the timing wheel T by means of the sliding sleeve S, in one end of which is a straight feather F engaging with the timing wheel. At the other end of the sleeve a spiral key S K works in a corresponding groove formed in a recess in the end of the cam shaft. Now, the longitudinal motion of the sleeve through the timing wheel causes the cam shaft E C partially to rotate, so that the relative position of the cams operating the valves and the crank shaft is changed. The action of the apparatus is, therefore, as follows:— When the controlling handle above the steering wheel is in its central position the levers are in the same relative positions as shown, and the can shaft is in its proper position for the normal running of the engine. By rotating the controlling handle to the right through about 120 degrees the throttle valve is opened to its fullest extent by the action of the upper groove of the spiral cam, the roller in the lower groove remaining stationary. When it is desired to convert the engine into a brake, the movement of the handle 120 degrees to the left causes the cam shaft to be turned backwards relatively to the crank shaft; and the carburetter remains shut off. When the extreme position has been reached the action of the exhaust cam shaft is to open the valves during what would be normally the firing stroke, and to close them during the normal exhaust period. In this manner it is obvious that the engine will work as an air compressor, drawing in air and compressing it at every stroke. A very powerful braking action is thus assured, quite independent of the hand and foot brakes, with less wear and tear and less liability to side-slipping on greasy roads.

The Brush 35 horse-power petrol omnibus is shown on the stand of the British Automobile Development Company, Limited, Belvedere-road, London. The special features of this chassis are the substitution of hornblocks and guides for radius rods, saving the road springs from lateral play; the spring suspension of the live axle, and the position of the driver's seat. The engine has four cylinders cast separately, and with valves all one side. There are five main bearings for the crank shaft, and inspection covers are provided for easy access to the crank chamber. Forced lubrication under a pressure of 15 lb. is provided for the main bearings. A double-deck omnibus is shown, of which the body is entirely built of steel.

Several noteworthy ideas are incorporated in the chassis exhibited by Commercial Cars, Limited, Luton, including an interrupted buffer drive, the invention of Mr. C. M. Linley, the object being to obviate the transmission of jars from the road wheels to the motor mechanism. The introduction of this buffer drive also overcomes the chief defect that has hitherto shown itself in connection with dog clutches in the change speed gear box. In fact, this interruption allows the dogs time to jump into engagement with each other without noise and without shock. It consists of a series of rubber buffers firmly gripped in channel-shaped radial arms which are secured to the shafts of the two gear boxes respectively. The arms are not connected mechanically, but lie in the same plane, so that the power is elastically transmitted through them to the rear axle. The gear box contains three parallel shafts. The central is the main shaft, coupled at its forward end to the engine. The other two are the counter-shaft — carrying the gear wheels, which engage with the corresponding wheels on the main shaft — and the cam shaft, which is rotated from the driver's seat. This cam shaft has formed upon it three cams, which, by means of ingenious lever mechanism, throw into gear the dog clutches on the central shaft to engage the various trains of gear wheels.

The Darracq Serpollet Omnibus Company, Limited, 2, Coleman-street, London, has an interesting stand on which the 30-40 horse-power steam omnibus is shown, together with a van intended for use by the Emigration Department of the Canadian Government as a demonstration vehicle. We give in Fig. 4 an illustration of the chassis of the steam omnibus, which for simplicity and weight will compare favourably with the vehicles propelled by the internal combustion engine. The engine, placed in the centre of the chassis, has two double-acting cylinders, 2.75in. by 4.875in. These are separated from the gear case containing the connecting-rods and distributing parts by the slide closing the cylindrical guides of the piston-rods. The engine casing also contains the differential gear connected with the crank shaft by means of two spur wheels, geared in the ratio of two to three. The chain pinions are mounted on shafts supported by bearings fixed to the side frames, and these shafts are connected by cardan joints to the first-motion shaft, so allowing for any spring or deformation of the frame. The valves, of the mushroom type, are placed on top of the engine. The steam generator is of the well-known Serpollet tubular pattern, and has 75 square feet of heating surface. The tubes are of Swedish steel — with the exception of the bottom one, which is of nickel steel — and all joints are outside of the boiler casing. The burner consists of a coil of steel tubing for vaporising the paraffin, a central body containing a filter and receiving the paraffin vapour for distribution to the branches carrying the burner nipples, and finally of nickel steel chambers in which the flame is formed. It has been lightened considerably compared with earlier forms, and is easily removable by means of a sliding tray, which is closed to prevent the flame being blown out by wind. The donkey engine has a double-acting steam cylinder working two pumps - one for water and one for paraffin. The ratio of the pumps is such that one volume of paraffin is delivered to ten volumes of water, but these proportions are capable of variation between certain limits. The speed of the donkey engine is regulated by a needle valve controlled by a lever on the right-hand side of the steering column. A hand-operated water pump is also provided, with a detachable lever for starting the donkey engine. The exhaust steam from the engine passes direct into tubular feed-heaters. These comprise a cylindrical shell containing tubes of small diameter.

The steam circulates in the shell, and the feed-water in the small tubes. On leaving the feed-heaters the steam is carried to the condenser at the back of the vehicle. This is of large capacity, serving for the purpose of expansion, and owing to its air-cooled surface brings down the temperature of the steam. From the condenser the steam reaches the multi-tubular fin radiator placed in the front part of the chassis, where it is reduced to the state of water and returned to the tank. The oil pump has two feed branches, one for the steam chamber of the engine, and the other for the steam inlet to the donkey engine. The oil pumped varies in direct proportion with the speed of the main engine. A special oil called Speedoline used for lubricating the engine, and a half gallon is said to be sufficient for a run of 100 miles.

Steam wagons are shown by

With the exception of the Yorkshire Company's wagon and the 2-ton steam wagon shown by Messrs. Ellis, the whole of these are familiar to readers of THE ENGINEER. In the 6-ton wagon made by the last-named firm a change has been made from the horizontal to the vertical type of compound engine. This has cylinders 4.5in. and 7.5in. by 7.5in., and is capable of giving 30 horse-power at a speed of 410 revolutions per minute with steam at 175 lb. pressure. The engine has link motion reversing gear, and is placed at the back of the driver, whence it can be easily removed, while all the working parts are enclosed and run in an oil bath. The casing is fitted with covers, which are easily removable. Motion is transmitted by a pair of spur cast steel gear wheels to corresponding wheels on an intermediate shaft, from which it is in turn transmitted to a sprocket wheel and differential gear on the live hind axle by a long chain. The boiler is of this firm's well-known horizontal double-ended type.

The illustration— Fig. 5 —shows the 2-ton compound steam wagon built by Jesse Ellis and Co., Limited, Maidstone. In the design of this vehicle the special requirements of a certain class of user to whom speed is of more importance than weight-carrying power have been considered. The van is designed to carry a load of two tons at a maximum speed of over 10 miles per hour, and will travel up a gradient of 1 in 7 with ease. The change-speed gear of the epicycloidal type gives three speeds forward and reverse, viz., 10.7, 6, and 2.8 miles per hour, and the facility of changing from one speed to another whilst in motion enables the driver to handle the van in the densest of traffic or up the steepest inclines. The engine is of the horizontal compound reversing type developing 25 indicated horse-power, working in a light dust-proof and oil-tight casing, thus ensuring perfect lubrication to all working parts, and is fitted with a lid on top and hand holes at the sides for inspection and adjustment. All bearings are of phosphor bronze and have long surfaces. The boiler is of vertical fire-tube type, fired from the top through central tube, made to burn gas coke or coal. It is constructed to work at 200 lb. steam pressure.

On the stand of the Kirkstall Forge Company, Leeds, two important inventions are shown. The first is Butler's axle for motor vehicles, the chief feature of which is the employment of two steel channels placed hack to back a little distance apart, and riveted on to a specially-formed central wing, which is stamped solid with the barrel or fork end of an axletree. As this central wing is formed with lips which fit above and below the channels on either side, there results a spliced joint of what becomes thereby an H section axle between the barrels. It is claimed that by caulking the lips of the central wings on to the channels all vibrating stresses are removed from the rivets. The steel employed has a tensile strength of 40 tons per square inch, an elastic limit of 27 tons per square inch, elongation 30 per cent., and contraction of area 55 per cent. This type of axle seems a great improvement upon the older form of tubular axle with fork ends shrunk on. The other novelty on this stand is Butler's reciprocating hub, which, it is claimed, provides a better method of lubrication than is obtained with hubs having no lateral play. The movement laterally is controlled by a plunger and helical springs in an ingenious manner.

In addition to petrol omnibuses, one and two-ton delivery vans, and a steam wagon, the firm of Sidney Straker and Squire, Limited, show a 30 horse-power petrol-electric omnibus chassis; the different gradations corresponding to the change speed being obtained by an automatically varied voltage and amperage given out by the generator, which is coupled direct to the engine. This enables the starting from rest to be effected under favourable conditions — that is to say, the current supply to the motors is then of a high amperage and a low voltage. As the speed of the vehicle increases, the amperage diminishes, and the voltage increases until the maximum speed of the vehicle has been obtained. The consequence is that the acceleration is rapid. In order to secure rigid alignment the dynamo frame is bolted to an extension of the engine crank chamber case, the whole forming a compact unit. Two motors are provided, each driving a road wheel independently, no differential gear being required. The motors are arranged to be suspended one on either side of the chassis, being supported from the main frame, and the motor shaft of each carries a hardened steel worm meshing with a worm wheel mounted on the inside end of a second motion shaft. To the outside end of this shaft is fixed a chain pinion driving the road wheel by means of a silent chain. There are thus two second motion shafts, each driving one road wheel, and eliminating the necessity for differential gear. The second motion shafts, together with the worm and wheel gears, run in oil-tight cast steel casings, and are mounted on ball bearings throughout. The electrical equipment is provided by the British Thomson-Houston Company.

A praiseworthy endeavour to provide a simple, light, and inexpensive delivery van or traveller's brougham is made by Sturmey Motors, Limited, Lotis Works, Coventry. This company has adopted as the propelling agent for these little vehicles a single-cylinder 8 horsepower Parsons engine, which uses kerosene as fuel. Most of our readers are already acquainted with this engine, but the chief features may be briefly recapitulated. The induction and exhaust valves are concentric and controlled by a single spring. The fuel, on passing into the inlet valve, impinges upon the surface of the hot exhaust valve, by contact with which it is vaporised and passed directly into the combustion chamber, where it is ignited before it has time to cool or deposit. In the Parsons vans and brougham this engine drives by means of a cardan shaft on to a two-speed and reverse epicyclic gear contained in an oil-bath casing, forming an integral part with the axle casing and dispensing with the use of a torque rod. The top half of this combined casing is detachable, disclosing all parts of the gear, which can be then readily dismounted. The axle is a live one, of the "floating" variety, the wheels being mounted on the axle casing, which takes the weight of the car and load. The clutch is a metal-to-metal cone, combined with the gear, and running in the same oil bath. The control is simple, consisting of three foot levers, pressure upon either of which puts either high or low speed or reverse gear into operation, and the removal of the feet from the levers automatically disconnects the clutch.

Although the marine section of the Exhibition is fairly representative of the motor boat industry, there are few new features or improvements to be noted. One of the most attractive stands is that of John I. Thornycroft and Co., Limited. This firm is represented by a motor launch. Veradaise II., 25ft. long by 5ft. 6in. by 18in. draught, and is propelled by a single-cylinder 6 horse-power petrol engine with reversing gear and Thornycroft propeller. There is also shown a 100 brake horse-power four-cylinder engine, 8in. diameter by 8in. stroke extended, for using petrol or paraffin as fuel. Motors of this type are now meeting with acceptance in marine circles for the propulsion of large cruising launches and yachts. In arranging the carburetter for two kinds of fuel a two-way cock is provided, so that when running on petrol the vapour from the carburetter can pass directly into the mixture pipe, and thence to the cylinder. When paraffin is brought into use while the engine is running, however, the oil goes into a vaporiser, which is heated by the exhaust gases.

Messrs. Linton Hope and Co., Adam-street, Strand, London, show the Dan engine, which is designed to use paraffin only, and has been extensively adopted on fishing vessels. It has the advantage of simplicity. The fuel is pumped into a heated chamber connected to the cylinder, but remote from the air and exhaust valves which control the admission and expulsion of the main charge. The oil is thus converted into a vapour without "cracking" and without causing a deposit to form upon the walls of the chamber. The vapour is not mixed with air upon its admission, but remains inexplosive until the following compression stroke. The makers have found that greater economy and more power is obtainable when the oil is injected into the vaporiser during the time the cylinder is discharging the burnt products from its previous charge through the exhaust valve than during the charging stroke.

Another paraffin motor is the "Kromhout," shown by Perman and Co., Limited, 29A, Charing Cross-road, London. The most conspicuous feature of this engine is that no carburetter or gas generator as usually understood is required. The oil is split up by passing through minute holes in a vaporiser seated directly under the induction valve, whence it can be easily removed for cleaning. To start the motor a small quantity of petrol is used; when this is consumed the vaporiser is hot enough to run the engine on paraffin. The paraffin is forced into the cylinder by means of a small plunger pump driven on an excentric on the two-to-one shaft. The exhaust valve is lifted by an excentric rod and slide piece driven by an excentric on the two-to-one shaft, and the small pendulum governor is arranged so that it is actuated by the same excentric motion. The governor is designed on the hit-and-miss system, and when it comes into action the slide piece ceases to lift the exhaust valve, and at the same time the fuel feed pump ceases to act. The governor is so constructed that when out of action the exhaust valve is lifted at every second revolution of the motor by the excentric. On the control lever being put in the neutral position, thus relieving the motor of its load, the force of gravitation on the pendulum weight of the governor overcomes the lifting effort of the governor spring, and the connecting piece between the excentric rod and the exhaust valve then misses the slide piece which operates the exhaust valve and the fuel feed pump. Therefore, until the speed of the motor slows down sufficiently for the governor spring to overcome the weight on the pendulum, the exhaust valve does not open and the fuel feed pump does not work.

There is a fairly representative display of machine tools. The exhibits are largely confined to those tools which are suitable for the motor car industry. C. W. Burton Griffiths and Co., Ludgate-square, London, show amongst other machines a 21in. swing Gisholt combination turret lathe, a 24in. Davis turret lathe, a triple-action semi-automatic chucking lathe, a Whiton gear cutter, and other tools.

Alfred Herbert, Limited, Coventry, shows in operation a hexagon turret lathe driven by an 8 horse-power electric motor. It is shown making 1in. hexagon-headed screws 12in. long. There are also on this stand capstan and combination turret lathes, a valve-grinding machine, and the Ducommun bevel-gear generating machine.

Ludwig Loewe and Co., Limited, Farringdon-road, London, show several kinds of milling machines, a 10in. by 5Oin. plain cylindrical grinder, a Tindel-Albrecht crank shaft lathe and a Rumpf screw-cutting lathe.

Selig, Sonnenthal and Co., Queen Victoria-street, London, show a new continuous spiral oil-grooving machine, a 30in. boring and turning mill, drilling machines, lathes, slotting, and shaping machines.

Quite a satisfactory feature of the show was the number of light motor vans suitable for tradesmen and shopkeepers. The requirements of this class of customers are somewhat difficult of fulfilment. Unlike large passenger-carrying companies with a number of vehicles, a running department, and a staff of mechanics, the tradesman only keeps perhaps one or two motor vehicles, and employs unskilled labour for drivers. The mechanical knowledge of these men is extremely limited. Simplicity of the motive mechanism, coupled with solidity and ample wearing surfaces, is therefore a necessary feature.

The Parsons van shown by Sturmey Motors, Limited, and illustrated on this page by Figs. 6 and 7, complies with the above requirements in a very large measure. We gave a brief outline of the principal features of the van last week. We may, however, repeat that the motor is of the single-cylinder vertical type, 4.5in bore by 6in. stroke, and gives 8 horse-power at 800 revolutions. It is placed under the driver's footboard and drives direct to the gear box without any intervening clutch. The gear is epicyclic, providing two forward speeds and a reverse, the changes of speed being effected by pedals and band brakes. The radiator piping is utilised to form a guard round the top of the van, thereby fulfilling a double purpose. The possibility of the use of paraffin as a fuel on this van should be an attractive feature. This is rendered feasible by Parsons' well-known principle, in which the exhaust valve is placed inside the induction valve, and the incoming oil spray is split up by the heat of the exhaust gases of the earlier stroke. For starting an injection of petrol is needed.

Alldays and Onions' Pneumatic Engineering Company, Limited, also made a feature of light commercial vehicles, but the motor mechanism is on the lines usual in pleasure vehicles. The engine for a 20 horse power van has four vertical cylinders, while a commercial traveller's car and a light van have two-cylinder engines with two cylinders. These engines are designed to use petrol as fuel, and there are the usual sliding gears. This firm also showed a railway inspection car, propelled by a petrol engine, and fitted with two high-speed forward and reverse gears.

Fig. 14, page 288, represents a 6-ton steam wagon, built by the Yorkshire Patent Steam Wagon Company, Limited, Leeds. This type of wagon has been designed to comply with the Local Government Board's regulations, and to deal with a total load of 10 tons, six tons being carried on the wagon and four tons on a trailer. The engine, which is fixed immediately behind the driver, is of the compound vertical type, with link motion reversing gear completely enclosed and running in an oil bath. The high-pressure cylinder is 4.5in. diameter, and the low-pressure 7.5in. diameter, with a piston stroke of 7.5in., and the engine indicates 35 horsepower at its normal speed. The crank shaft is 2.75in. diameter, machined from a solid mild steel forging. The intermediate shaft is also of mild steel, 3in. diameter. The gearing is of cast steel throughout, and arranged to give speeds of three and six miles per hour. The drive from the second motion shaft to the live hind axle is by a Renold roller chain running on machine cut sprockets. The back axle is forged from best Yorkshire iron, and 4.5in. diameter. Two independent brakes are fitted, one being a powerful screw brake acting directly on the tires of the driving wheels, and the other a band brake acting on a drum on the second motion shaft, and actuated by a foot lever on the driver's footplate. The main framing is of channel steel, 6in. deep by 3in. wide by 0.5in. thick, strongly braced with steel cross stays and gussets. The vehicle is spring mounted on both axles, the front axle being of the divided Ackermann type, actuated by a screw and nut. It has a central support, and is free to rock, and so accommodate itself to any unevenness of road surface. The water tank is slung between the main frame, and is of very large capacity. The water is fed to the boiler by two injectors fixed on the front of the boiler. The road wheels are of the artillery type; front wheels 3ft. diameter by 5in, wide, and the hind wheels 3ft 3in. diameter by 10.5in. wide, with diagonal cross strips. The boiler is of this firm's double-ended locomotive type, and is constructed for a working pressure of 175 lb. per square inch.

Figs. 11 and 12, page 200, represent two site views of the Straker-Squire petrol electric omnibus chassis, with British Thompson Houston electric equipment. The engine is of the four-cylinder tyre, with cylinders 5in. bore by 5.125in. stroke, and develops 32 brake horse-power at 900 revolutions per minute. The main feature of the engine is the position of the camshafts actuating the valves and ignition tappets at the top of the cylinders, so that the inlet and exhaust valves can be placed at opposite sides of the cylinder, and yet both can be operated from the one camshaft. The speed of the engine is regulated by a centrifugal governor designed to cut out at 450 revolutions per minute when running light, acting direct on a throttle valve. An automatic carburettor is fitted. The ignition is by low-tension magneto. The continuous-current dynamo is bolted directly to an extension of the engine crank case, and is rated at 15 kilowatts 230/65 volts at 900 revolutions. It is of the automatic regulating type, designed to maintain a constant output at a constant speed on the engine irrespective of the varying load-demands of the vehicle. In other words, the product of volts and amperes is at all times a constant, for as the demand for amperes increases, as for example, when the vehicle is climbing a grade, the volts correspondingly decrease in such a manner that the load, and, therefore, speed of the engine, remains unaltered. This is brought about by a suitable arrangement and design of the dynamo windings, and without the use of moving contacts. Each motor is noted 7.5 kilowatt constant input, 115/65 volts, 1,400/500 revolutions. They are series wound, and are totally enclosed, with removable aluminium covers, which completely protect the windings from water.

The system of control is simple. At the driver's right hand, in the position usually occupied by the change-speed lever, is mounted the "operating box" containing the control lever, which is coupled by means of a chain to operate the controller proper. The latter is placed below the footboards in a position close to the motors and generator, thus reducing the length of cables to a minimum. The controller provides the following motor connections:- First speed forward with the motors in series; second speed forward with the motors in parallel; "off" position. The reverse is effected with the motors in series. In the "operating box" is also mounted a small resistance and control switch in circuit with the generator field. A foot pedal is arranged to be coupled to the engine governor and to this field control switch in such a manner that when the pedal is fully depressed the engine is governed to run at 450 revolutions per minute, and at the same time the switch is moved to insert a resistance in the generator field sufficient to reduce the main volts practically to zero. No current then flows to the motors, and the vehicle is brought to rest. On releasing the pedal the first movement cuts the resistance out of the generator field, causing sufficient current to flow to the motors to start the vehicle, which will continue to run slowly, the engine speed remaining governed at 450 revolutions per minute. On entirely releasing the pedal the governor is "held up," allowing the engine speed at once to increase to its normal 900 revolutions per minute, and the speed of the vehicle is accelerated. The speed is, however, prevented from exceeding 900 revolutions per minute by the influence of the generator. The increased torque required at starting, or on climbing grades, has no influence in reducing this speed, owing to the automatic constant load demand of the generator, which ensures the engine speed remaining unaffected whatever torque may be required at the road wheels. The engine, therefore, runs at its normal speed, and develops its full normal power during the whole of the accelerating period. The vehicle is started on the top speed, i.e., the motors are in parallel, while the main circuit is not broken in stopping and starting, and, therefore, no sparking occurs at the controller contacts. The controller is only operated for reversing, and in climbing grades exceeding 1 in 20, when better results may be obtained by running on the first forward series position, but, on the other hand, no damage can occur to the equipment if the driver neglects to change the speed.

In cases where it is necessary to travel for long distances at reduced speeds, it is not convenient to regulate by the foot pedal, but for this purpose a hand lever is provided, which independently controls the engine speed and allows the pedal to be released. Under certain circumstances, as, for example, when climbing grades, it is desirable to accelerate the engine speed for short periods, in order to obtain the maximum power available. This is provided for by coupling the hand lever to the field switch in correct sequence, and in such a manner that after the hand lover has been moved to a position corresponding to an engine speed of 900 revolutions per minute, a further movement inserts a portion of the field resistance, which alters the load demand of the generator and permits the engine to increase in speed, and deliver to the generator its maximum power. By this means full advantage can be taken of the additional power that may be obtained by running a petrol engine for short periods above normal speed. The vehicle is stopped and started by a foot pedal, which can be worked with any degree of suddenness without causing shock at starting or damage to the engine or transmission. The speed is controlled in traffic by the same pedal, or for long distances by a hand lever, by which the engine speed can also be accelerated at will. Under running conditions, the hill that would necessitate a change in a mechanical gear is negotiated by the electric transmission at the maximum speed for each particular grade without any action on the part of the driver, the automatic generator supplying the motors with the necessary current to enable them to develop the torque required, while at the same time the engine load, and, therefore, its speed, is also automatically kept constant.

The illustration —Fig.l3- represents the chassis of the new 28 horse-power petrol. engined omnibus, built by Milnes-Daimler, Limited, 221, Tottenham-court-road, London. A number of omnibuses with this new chassis are now running in London. Several important improvements have been introduced, including a frame and perch bars, all of pressed steel. The engine has four cylinders cast in pairs, 4.625in. diameter by 5.5in. stroke. The two pairs of cylinders are well separated to allow of a long central bearing. The pistons are 6.5in. long, and have annular oil-distributing grooves, one each above and below the gudgeon pin and one near the lower end. The crank shaft is of chrome nickel steel, the three principal bearings being 4in. long by 1.875in. diameter, while the crank pins are 3in. long by 1.875in. diameter. The valves, of course mechanically operated from two cam shafts, are on each side of the crank chamber, and these shafts are interchangeable. They are cut from chrome-nickel steel, and the cams are machined from the solid, the whole being afterwards hardened and ground. The Simms-Bosch low-tension magneto system of ignition is provided, the armature being gear driven. The magneto apparatus is placed in an accessible position and secured to a bracket by a steel strap and shackle bolt, which makes it easy to dismantle. Forced lubrication is fitted to the crank shaft bearings, and the shaft being hollow, the oil finds its way to the big-end bearings. The pressure of oil is maintained by a small force pump, the ram of which is worked by a crank on the tail end of the inlet valve cam shaft, and an indicator on the dashboard shows the pressure maintained. The motion of the engine is transmitted by a leather-covered cone clutch. The clutch shaft is attached to the first shaft in the gear-box by flanges, and carries the sliding gear wheels, which are bolted to sleeves having six internal feathers corresponding with key-ways cut in the shaft. The sliding gears are controlled by a lever, working in a gate, and this actuates one of three selector rods. The secondary shaft is situated beneath the first- motion shaft, and its gear wheels are bolted to flanges, which are integral with the shaft. The forward gear ratios are: 2.5, 5, 8.5, and 12 miles per hour, and the reverse gives a speed of 2.5 miles per hour. The gears are of chrome-nickel steel. A cardan shaft transmits the motion from the gear-box to the differential gear. Both ends of the shaft are furnished with universal joints. The joint at the fore-end is of the usual type, whilst the rear extremity is provided with a joint of special design. A toothed pinion is bolted to the shaft, and this is an easy fit in an internally-toothed box, forming the front-end of the short shaft which drives the differential gear. The pinion has teeth of a special form, to allow of either horizontal or vertical movement. The differential shaft drives the back wheels by pinions, which mesh with internally-toothed rings upon the inner side of the driving wheels, Three brakes are fitted. The foot pedal acts upon a drum, bolted to the forward end of the secondary shaft in the gear-box; the second, also operated by a pedal, has two drums, one at each end of the differential shaft. The drums are water-cooled, the supply of water being regulated by two taps on the dashboard. The third brake acts on the inner sides of the back road wheel rims. The blocks are of V-section, fitting into correspondingly shaped grooves. The perch bars, instead of being parallel with the main frame as formerly, are brought close together at the front end. The back axle is a straight forging of H section, and the journals are 8.875in. long by 3in. in diameter. The front axle is of similar section also, nearly straight. The back springs are slung outside the frames by shackles. They are 4ft. 2in. long, having nine leaves, 3in. wide by 0.5in. thick. The spring shackles are provided with grease cups, so that they can be effectively lubricated. The design of the whole of the chassis gives the impression of having been well thought out. The weight has been kept down apparently without sacrificing stiffness and durability.

The carburetter and valve for admitting the air into the cylinders on the Saurer vehicle made by Messrs. J. and E. Hall, of Dartford, is shown clearly in section in Fig. 8. The carburetter has two jets fed from a float chamber. When the engine is running light the vacuum produced is insufficient to open the clack valve C, and thus the supply of gas is limited to that produced by the one jet on the right-hand side. When the speed of the engine increases, and more gas is required, the valve C is forced from its seat and the second jet comes into action. The supply of gas is regulated by the throttle valve D, which is moved up and down by the rod E. This rod is actuated from the governor. When the engine is being used as an air brake, the cylindrical valve F is closed by hand from the steering column, as shown in the diagram Fig. 8 in last week's issue, and pure air to the cylinders is admitted through the valve G. In the sectional drawings B, B1 are the branches which lead the mixture from the carburettor to the engine, and H is the pipe for admitting pure air for the air brake. The relative movements of the valves will be followed from the drawings. Fig. 9 shows the system of forced lubrication adopted on the Saurer engine. The oil from the crank chamber is forced by means of a gear-driven pump through a hollow spindle K and strap into a hole in one of the main bearings, as shown, and from this bearing it is caused to flow through holes in the crank shaft to the various crank pins. Fig. 10 shows the arrangement of the gearbox and second motion shaft. This provides four speeds and a reverse, but the pinion for the latter is not shown. The motion is transmitted from the first motion shaft M through one of the various combinations of gears to the lay shaft N, on the end of which is a bevel pinion, gearing with the ring P, which encircles the differential gear. Ball bearings are fitted throughout, and the teeth are of ample proportions. The gears are moved by one lever and a gate and selector rods. The differential gear case is a mild steel forging bored out. The crank shaft, intermediate shaft, gear and chain-wheel shafts are all of chrome nickel steel. The main frame of the vehicle is composed of straight mild steel rolled channels reinforced at the section submitted to the greatest stress by flanged nickel steel plates, riveted in place and stiffened in front by a cross member of box section. The engine has four cylinders, 110 mm. bore by 140 mm. stroke, and is capable of developing 38 horsepower. Two systems of ignition are provided, namely, the Simms-Bosch high-tension and alternative battery. The ignition timing is by hand. The vehicle is British built throughout with the exception of the road wheels, chains, magnets, and some small accessories.

A new taximeter was shown on the stand of S. Smith and Sons, Limited, 9, Strand, London. It has been constructed under official advice to meet the requirements of the London cab. It has two dials. On the left-hand dial time is shown by the hour and fractions of an hour, and on the other dial the distance traversed in miles is shown. These dials cannot work together. When one is in action the other must be stationary. Thus, when the distance traversed is between two and three miles, and the fare gets out, the cabman has only to press a lever, and the time he is kept waiting will be recorded, showing each fifteen minutes or part thereof. On starting, he will re-press his lever, and it will continue to record the distance traversed. Therefore, at the end of the journey there will be a record in full view of the passenger, showing exactly the number of miles traversed and the time kept waiting, even after several stops have been made. A good feature of this instrument is that it records the distance both inside and outside the four-mile radius. Thus on passing the radius, the cab-driver has only to press a lover and a different-coloured hand will remain at the distance traversed up to this mark; the black hand will continue to show the distance traversed outside the radius. Thus, if a passenger is set down outside the radius, he can see how far he has travelled inside the radius and how far outside, and from the table of fares underneath the instrument he can easily see what the correct payment should be. Should the passenger, however, continue his journey and be driven back inside the radius, this extra hand would be ignored and he would pay the ordinary fare.

The firm of Hans Renold, Limited, Manchester, showed the latest improvement in silent driving chains, in which the links are not allowed to bear directly on the rivets, but carry removable hardened bushings which turn with the links. This arrangement gives to the rivets a bearing the full width of the chain. In order to demonstrate the principle embodied in the construction of these chains this firm had an electric motor driving by means of a sprocket wheel and chain, an idle chain wheel on one side of the motor, and on the other side of the motor the discs of a stroboscope. The main chain is of the silent pattern. The transverse shaft carrying the stroboscope is fitted at its remote end with an arm bearing an eye-piece on a level with the slots in the disc, the slots being in line with the chain links and the wheel teeth. Viewed through the eye-piece, and when in motion, the teeth and chain appear practically at rest, and the positive contact between the two is shown in a very clear manner.

A solid rubber tire for heavy vehicles, which has been designed to prevent creeping of the tire round the rim, was shown by Messrs. J. E. Hopkinson and Co., Limited, 121, Cromer-street, London, W.C. The inner circumference of the tire is provided with wedge-shaped strakes, which fit into corresponding grooves in the steel rim. The treads are vulcanised on to a hardened base, which is moulded round an endless steel band, thus preventing the tire from stretching. The tire is held on the rim by detachable rings.

See Also


Sources of Information

  1. Motor Car Journal of 10th March 1907
  2. The Engineer of 15th and 22nd March 1907