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Doc's Exacto-Built Meccano Breakers Yard Crane

Hi folks, Doc here. Here's yet another model that I built with the Exacto Crane and Helicopter Set: the Breakers Yard Crane. Some of you Erector fans will recognize the similarity of this design to the Trumodel Stiff Leg Derrick model from the Classic Period of Gilbert Erector. In point of fact, the model shown in this pictorial is a standard stiff-leg derrick, but with a twist: it features an operator's cab mounted on the central mast. The model gets its name from the specific application that the original version was patterned after: a crane used in a ship "breaking" (demolition) yard.

Stiff-leg derricks have been in continual use for centuries. During all of that time, they have remained virtually unchanged: the general design was so simple and effective that change was never really necessary. These devices were a standby of 19th century construction for everything from buildings to shipyards, mining to lumber mills, railyards to docks, and they are still fairly common today. In their simplest form, they are nothing more than a vertical central mast that is held upright and braced by a simple triangular framework, or A-frame, consisting to two fixed legs that extend back and down from the top of the mast. These legs are either anchored at their lower ends, or attached to a solid base (as is the case in the model shown on this page). Sometimes, particularly on smaller derricks (often made from heavy timbers like the one shown above right), these "legs" were nothing more than guywires made from heavy cable or even chain. The central mast, which rotates freely, has a long lifting boom attached near its lower end. This boom was raised and lowered by way of machinery either mounted directly onto the mast (sometimes nothing more than a manual crank with gears and a ratchet), or located remotely.

The framework of the Meccano version shown in the photos below is constructed primarily from angle girders. It features an X-shaped base with a square girder central mast (formed from two angle girders). The operator's cab and winch assembly are mounted on the mast, which pivots about 240º. The enclosed cab has a curved clear canopy and lower fascia. The motor, which is mounted to the bottom of the cab, raises or lowers the hook, while a manual crank is used to raise and lower the boom. The finished model measures 12" tall by 24" long.