The Latest Track-laying Tractor
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A New International Model with Simple, AllMetal Tracks
TN our report of the exhibits at the ...Royal Show we referred briefly to the new track-laying machine exhibited for the first time by the International Harvester Company, of Great Britain, Ltd., Harvester House, 259, City Road, London, E.C.1. Now we are able to give further details of this interesting model which is, of course, additional to the well-known wheeled types of this make.
This new machine ia known as the TracTracTor ; it employs a fourcylindered engine of 3i-in. bore and 5-in, stroke, running up to 1,250 r.p.m. Fuel is fed by a Stewart-Warner pump from the 18i-gallon tank to the SchebIer carburetter. The last-named can deal with petrol or paraffin, according to the control of the baffles in the manifold. Air passes through an oil-type cleaner to the carburetter. For ease of starting an iMpulse mechanism is installed on the international magneto.
A single-plate clutch, working dry, is controlled by pedal; this takes the drive to the three-speed-and-reverse gearbox, which has a centrally mounted
control lever. The travelling speeds are 1.'77 m.p.h., 2.73 m.p.h. and 3.84 ra.p.h..in the forward direction and 2 m.p.h. in reverse. The drive is taken through a differential to the sprockets which rotate the track. By means of a brake for each tfack steering is effected, the inner track being retarded while turning.
Laterally braced twin channels form the frame for each track assembly ; these are pivoted, at their rear extremities, from a cross-member of the main frame, and the two are coupled by a spring. Below the channels are the bearings for the rollers which carry the lower run of each traCk. At the forward ends of the assemblies are idler wheels with a central flange in each case; this guides the chairs.
Adjustment for track tension is by means of a rocking mounting for the idler; the axle of the last-named is supported in arms which can be moved forwards by rotation of a nut on the screwed shank of a forked member, provided with a substantial abutment. This system is simple and readily accessible. Each track plate carries a vertical, integral, tapered grouser.
A feature of this machine is the care taken to enclose the bearing surfaces of the parts distinct from the track proper. The machine is 9 ft. 6/ ins. long, 4 ft. 6i ins, wide and has a total height of 4 ft. 7 ins. The area of ground contact is 4 ft. 4i ins. by 10 ins. The modest dimensions make it a handy outfit.