The Selden Two-ton Chassis,
Page 6
If you've noticed an error in this article please click here to report it so we can fix it.
Two Models Available : Final Drive Either by Chains or Worm.
The question of the suitability of the chain or live axle as the final drive for commercial vehicles _has been the subject of much controversy. Personally, we are still of opinion that there i4 much to be said on both aides. Intending purchasers of the Selden two-tonner are in a position to have their own personal tastes, in this respect at least, catered for, the Selden Manufacturing Co. of the United States having the enterprise to manufacture two Models of the same capacity, in one of which the final drive is by roller chains, whereas the other is fitted with what may perhaps be referred to as the more modern method of drive by overtype worm. In all respects save the one mentioned, these chassis are .identical.
The engine has four cylinders cast en bloc. They are a.' the Lheaded type, and, judging by extenors, provided with ample space for cooling water. The usual attributes of the modern well-designed engine are discoverable on examination. The cooling water is circulated by means of a centrifugal pump situated on the off side of the engine and placed immediately behind the timing-gear case. A universal coupling ie interposed between the pump spindle and its driving shaft, and the spindle itself is produced to the rear of the pump and receives a second similar coupling through which the drive is taken to the magneto. It should be noted, however, that facilities are provided in this second coupling for ready adjustment of the timing of the magneto. This latter accessory is of the American Bosch high-tension type. The shaft from which the drive for the pump is taken is prolonged in a forward direction, and projects through the timing-case cover. To the front end is keyed the fan driving pulley. On the opposite side of the engine is situated the Stromberg carburetter, as well as the exhaust pipe. A gear-driven governor, the mechanism of which is enclosed so as to obviate the possibility of its being tampered with by any unauthorized person, controls this carburetter and limits the engine speed as may be desired. The lubrication of this component has evidently been the subject of some considerable and careful thought. An oil pump driven from the crankshaft draws oil from a reservoir, pumping it thence to the main bearings. Any excess overflows into troughs into which the connecting rods dip, thus • gathering sufficient for their own lubrication, as well as by splash providing for the oiling of the gudgeon pins and cylinders. An indicator on the crankcase serves to assure one as to the level in the reservoir. Another one on the dashboard enables the working of the pump to be verified.
The clutch and flywheel, while occupying their customary positions immediately behind the engine, are totally enclosed. The clutch is of the dry-plate type, and requires very little attention in order to keep it up to the required pitch of efficiency. A large hand hole, however, is provided in the casing which would readily allow of any minor adjustment being made. The gearbox is manufactured by the Brown Lipe Co. By its means three forward speeds and one reverse are possible.
Behind the gearbox, of course, points of difference between the two ehasais require to be taken into Account. Dealing first of all with the live-axle machine, it is to be noted that from the gearbox to the overtype worm runs a long propeller shaft. This is tubular in construe
tion, so as to be more than ordinarily stiff, and thus avoid any tendency to whip. The rear axle is a full floating one of the well-known Timken-David-Brown worm type. It follows naturally that the bearings, both of this and of the front axle, are also of the Timken type.
The steering gear is of the screw and nut type. A wheel of generous proportions is provided, and in the course of a trial run on this vehicle we were able personally to observe its freedom and ease of operation. In the first one or two chassis that have arrived, the column is placed on the left-hand side, as our illustration shows. In future, however, this will not be the case, as arrangements have been made for the right-hand steering to be standardized on the models sold in this country.
The usual brakes are provided, both of which operate on drums on the rear wheels. A point we noticed in this connection is that they are not compensated. Means of. readily adjusting the position of the shoes in relation to the drums, however, are available. No torque oi radius reds are provided, the functions of these accessories being carried out by the top leaves of the rear springs.
Turning now to the chain-driven model, it may be noted that the propeller shaft is carried in a tube which is itself a forward extension of the bevel drive and differential ease. The latter is carried in brackets bolted to the side members of the frame. From an examination of these brackets, it is evident that the tube enclosing the propeller shaft also serves the purpose of a torque tube. The differential gear is of the bevel type, and is carried in Timken roller bearings. The cress-shafts carry at their outer extremities the foo•tbrake drums, to which are bolted the chain sprockets from which the drive to the chain wheels bolted to the rear road wheels is by roller chains. Very substantial radius rods transmit the thrust from the rear axle to the differential casing. It la, of course, transmitted thence through the brackets holding it to the frame.
Features common to both chassis are : the adequate springing, which includes also supplementary coil springs on the top of each of the customary semi-elliptic road springs, and a substantial wellbraced frame. The wheelbase may be 10 ft. 10 ins. or 12 ft. 6 ins. The price of the chain-driven chassis, complete with driver's seat, horn, lamps, tools, etc., is £475; that of the live-axle one, with similar equipment,