W1400 Walking Dragline
As featured on the front cover of the Meccano Instruction books during the 1960s. This model is based on the model plans rescued from Binns Road by Jim Gamble and updated by Ian Stoney.
The model has walking shoe mechanisms and a (revised) gearbox. The levers control slewing, luffing, hoisting and dragging.
Having rejected the original gearbox, and deciding (after I had built it) to scrap the recommended modified gearbox, I designed my own. The three motions for hoisting, luffing and dragging were each given a Meccano MO motor driven by a worm and 57 tooth gear. This ensured electronic forward and reverse control and automatic locking of the cable drums. The slewing was taken care of by fitting a Meccano 6 speed geared motor set at 60:1 and the walking mechanism was driven by a DecaPerm motor. Everything was driven by an onboard 6 volt rechargable battery, with a 1 metre cable attaching the GWDL to the hand held control box. A few embellishments include the aircraft navigation flashing lights, jib flood lights and Walking shoe hazard beacons.
So, does it walk? Well the answer to that is yes, and № I now have so much torque at the walking shoe mechanism that the chain jumps. This has the effect of causing the shoes to go out of sync and the whole GWDL wobbles from side to side. The prototype W1400 only walked backwards (it just slewed to the opposite side that it wanted to go), so that was the solution. Instead of trying to get it to walk forwards and backward, I could add a tensioner sprocket to the chains to ensure that they never jump.
A scan of an old booklet (50 pages, Adobe PDF format, 7 MB) issued by Stewards & Lloyds on their new W1400 Giant Walking Dragline can be downloaded from this website by clicking here. This is the machine that inspired the Meccano model and the original Meccano Magazine articles. The firm has long since ceased to exist and the book is out of copyright, being over 50 years old.