Berna Motors, Limited.
Page 14
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Exhibits:—Three Lorries; Bus Chassis ; 3o-35h.p. Engine.
This exhibit comprises a 2-cylinder, 16h.p. chassis for a 2-ton load ; a 2cylinder, 2o-24h.p. rail-sided van for Inde Coope and Co., Ltd.; a 2-cylinder, slow-speed-engined chassis for a 5-ton load ; and a 4-cylinder, 3o-35h.p. chassis tor omnibus or lorry work.
The last-named exhibit is the principal one, and its engine has cylinders 4 inches in diameter, a piston-stroke of 6 inches, and develops its normal power at 800r.p.m. The cylinders are cast of " sulzer " alloy. Both inlet and exhaust valves are on the same side of the engine, and mechanically operated. The inlet valves have a variable lift and, if desired, can remain entirely closed. The engine is lubricated by a small spur-wheel pump at the base a the crank chamber. This pump keeps a separate chamber constantly charged with oil under pressure, the intensity of which can be adjusted by a springcontrolled release valve. Low-tension magneto ignition is used.
The clutch is of the leather-faced type, 20 inches in diameter, and operated by a pedal in the usual manner. The act of de-clutching closes the throttle, and prevents the engine from racing. The operating bridle is on ball bearings. The change-speed gear-box is made of " Weichguss " cast steel, and in it provision is made for four speeds forward and one reverse, with
through drive on top speed. The gear wheels are made from " Bismartshite " steel, the width of the teeth being I 3-16th inches.
The gear shafts are mounted on bal bearings, of which there are double sets at each end. The transmission from gear box to countershaft is by
cardan shaft. The countershaft is mounted on perch-bars, or radius rods, built up of two channels, with the webs outward, presenting a very stiff appearance. The ends of the differential shafts terminate with tempered steel pinions, which mesh with internally-toothed rings fitted to the rear road wheels. The whole of this gear is enclosed, and runs in grease. Ball bearings are fitted throughout, including the road wheels, which run on
balls inch in diameter.
• The channel-steel frame is of rolled section, 6 inches deep, with an angle frame of angle section 4 inches by 2 inches. The semi-elliptic springs are made by the famous French firm, Lemoine, of Paris, but in all other respects the chassis is of Swiss make. The petrol tank has evidently been made with a view to withstanding a lot of knocking about, its thickness is inch; it is made of sheet copper and close riveted. Its capacity is about 20 gallons. The usual foot and lever brakes are fitted, and the road wheels are of cast steel with " Duro " tires.
The 2-cylinder engine on the 5-ton chassis has cylinders isomm. in diameter, and a stroke of t8ornm.; it develops--24h.p. at 600 revolutions per minute.
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