Model Building Plan....

Including 'Virtual Mec' drawings by Edmundo Veiga.

David Lawrence's 'Rope Climber' - Winner of the 2006 W.L.M.S Challenge Event

Article about the model publshed in the Southern California Meccano and Erector Club newsletter Vol XXX No4 Fourth Quarter 2006

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My particular Meccano weakness is for Challenge Events and Races. I like to use my few remaining little gray cells to conjure up designs to suite the challenge event specification. These events are run by a small number of the major Meccano clubs around the world. At the appropriate time I parcel up my model(s) and mail them to a 'proxy mechanic' in a far-off country - someone who will enter my model in the event and mail the model back afterwards.

My latest challenge event entry needed the fastest model to climb a 1/2" diameter rope. The spec outlawed a 'mangle-type' movement and called for a hand-over-hand style of motion. The event was run on November 18th 2006 by the West London Meccano Society in England (my birth country). My model shown here took first place.

My method for doing these things is to start with a rough design and progressively improve it as I go along. I build one model and then start building a second rather similar model but making alterations to overcome any deficiencies that become apparent in the first model. I then carry out comparison tests to compare the performance of the two models. The better of the two models I put to one side. I then start altering the poorer performing of the two models, again amending features that did not work well last time. This procedure is repeated maybe ten or more times. Sometimes, as in the case of the rope climber, a third model is built when the better choice of the two models is marginal.

Basically the design involves two strip frames that are hinged to one > > another and oscillate by means of a powered Triple Eccentric. At the non-hinged end of the frames are spring-loaded gates, through which the rope is fed, which allows the rope to slip only on the non-climbing part of the cycle.

A cantilever MO motor with gearbox and train of gears provide power to the Triple Eccentric. The battery box is out rigged on an arm to act as counterbalance enabling the machine to remain approximately horizontal. The lighter the model can be yet still remain strong enough not to distort, will provide more power to the climbing operation, and therefore will be faster.

I acknowledge the kindness and technical skill of my Proxy Mechanic, Paul Joachim - Chairman of WLMS. This interesting challenge event was designed > > by Chris Bourne, WLMS Newsletter Editor.

by - David Lawrence