Rubber Track Drive
Built by Ralph Laughton in January 2012
Someone on Spanner or another of the Meccano forums pointed out that a plastic 19-tooth pinion fits inside the plastic drive ‘sprocket’ (cylinder) and engages with pre-moulded teeth making a non-slip union between the parts. As far as I can see Meccano have not used the design feature in any of their instruction book models.
This may not be new to some of you, but it was to me. Inspecting the drive cylinders there are two different parts. The grey ones have a full lattice of ridges on the cylinder’s surface but have only three teeth internally that will locate with the gear wheel. The bright green cylinders have a full compliment of teeth and a broken lattice of ridges on their face. As far as performance goes this seems to make little or no difference.
Mounting axles 4” apart (e.g. holes 2 and 9 in an 11-hole strip) allows the rubber tracks (from the 15 model Multimodel set) to be mounted with enough tension to be driven very successfully.
The first prototype was hurriedly put together using French tri-axle parts as it has no steering capacity. A more sophisticated version of the tracked drive using two motors, conventional axles and the yellow plastic, brass bossed pulleys makes the second prototype. Free wheeling hubs are made making good use of the brass bosses alone that we all get left with when the yellow pinion degrades and splits away. Arranging a fixed hub on each side of the chassis means that steering can be achieved by driving the axles in different directions or simply stopping one track.
More work to be done here…