THE NEW EXPRESS BUSES FOR PARIS.
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The Leading Characteristics are One-man Control, Three Brakes—One Servo-assisted and Acting on all Four Wheels—and Pneumatic Tyres.
WE HAVE on several occasions made reference to the new type of express bus which is being placed on certain routes in the French capital.
We have now received details of the new 20 h.p. one-man-controlled 25-seater Renault bus. This is of the frontentrance type, with a light grill-type door controlled from the driver's seat, the steps at the front being interconnected with this operating gear, so that, as the door shuts, they fold up.
The chassis has certain interesting features, including serve-assisted fourwheel braking. Actually, there are three brakes. Two are operated by band levers situated side by side one acting direct on the wheel drums and the other on the transmission shaft behind the gearbox. The third brake is operated by a pedal, and takes action on all four wheels through a servo mechanism.
Following usual Renault practice; the radiator is situated immediately in front of the dash.
The engine is a four-cylindered mono.
bloc, with a bore of 100 mm. and a stroke of 160 mm., provided with an aluminium crankcase. The crankshaft is carried by three main bearings. Nickel steel of high tensile strength is employed for the valves, and the camshaft is in one with the cams.
The whole arrangement of adjustable tappets and valves 'is protected from dust and dirt by a plate. The oil in the engine is circulated by a gear-type pump driven from the camshaft. In the first place oil is sent through a filter, where any impurities are arrested; from there it is directed to the three main bearings, froM which, it travels to the .big-ends, and is then thrown against the cylinder Walls staid other parts.
Carburation is attended to • by a Renault device with an automatic air valve controlled by a hydraulic daslmot. It possesses, a regulator for hot and cold air and is easily demounted for cleansing.
Ignition is by high-tension magneto driven from the camshaft by helical gears through the medium of a transverse aleif t and flexible coupling. The motor is restricted to a speed of 1,600 r.p.m. by .a totally enclosed centrifugal governor, also driven from the camshaft and so arranged that it can be sealed to prevent interference. Thermo-siphonic circulation is employed for the cooling water, and the air is sucked through the radiator by vanes on the flywheel. The power is conveyed through an internal leather-faced cone clutch provided with spring inserts to give smooth engagement. Between this clutch and the gearbox is a double universal joint completely enclosed. Four speeds forward are provided, and the shafts are mounted on ball bearings, the ends being provided with turbinetype oil retainers. The change-speed gear, clutch and brake pedals and accelerator are mounted on two supports carried by the gearbox casing. There is only one universal joint in the propeller shaft, and the rear half of this is enclosed in a tubular torque member, the front end of which is carried in an exceptionally powerful cross-Member. In our chassis illustrations the steering gear is shown at the right of the chassis, but in actual practice the driver sits and steers at the left, so that he is in a better position for observing traffic, and is also out of the way of the incoming and outgoing passengers.
Final drive is by bevel gears in an axle of the vertical banjo type. The Wheels are all provided with pneumatic tyres, 1,025 mm. by 185 mm., twin at the rear and single at the front. Lighting and starting are effected by a dynamotor eon_ nected to the crankshaft by an enclosed silent chain. This is an unusual feature to find on A h6avy vehicle.