Stone Lifter - An Appropriate Technology

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Stone fences, paralleling country roads, record the passage of the stone lifter. Pattern books guided local craftsmen in their construction. This was especially true in frontier areas where the need was greatest. Industrial advances gave rise to modern factories, which also turned out stone lifters. One manufacturer promoted their design as being capable of lifting a 5 ton boulder.

Stone Lifter – Employing Mechanical Advantage

Stone Lifter - Lifting Mechanism

The above illustration isolates the stone lifting mechanism. A steel axle traversed the wooden frame from side to side. Hooks suspended from attached chains secured the stones. The wooden wheel attached at one end of the axle provided the lift. In this example, the hardwood wheel had wooden teeth bolted to either side of the wheel forming a V-shaped groove. A length of rope nestled in the groove was wound around the wheel. When pulled it turned the wheel and raised the stone. This was a practical application of the principle of mechanical advantage. Larger wheels produced greater mechanical advantage.

For smaller stones, of a few hundred pounds, manpower was sufficient to get the job done. For larger boulders, draft animals were used to pull the rope. The larger boulders only had to be lifted enough to clear the ground. They were used to form the foundation of the stone fence. The smaller stones would be lifted higher to clear existing levels of construction.

Stone Lifter – Locking Mechanism

Stone Lifter - Locking Mechanism

With the stone suspended above the ground, the problem became how to keep it there. The locking mechanism, illustrated above, provide the solution. A sliding wooden beam was moved across the frame to engage the wooden teeth on the lifting wheel. This was accomplished by shifting a lever, that pivoted on a few metal parts fabricated by a local blacksmith. This arrangement eliminated the need for a metal ratcheting system.

With the suspended stone locked in place, the stone lifter could be manoeuvred over a fence to a desired location. After opening the locking mechanism, the stone was lowered into place.

Why This Technology Was Appropriate

Wood was plentiful and available locally. Metal had to be transported often a great distance and at great cost. Using hardwoods minimized the need for metal. The owner of the stone lifter could make many repairs to the wooden components, such as the teeth on the wheel. This technology was also appropriate to working with horses. They applied steady pressure, with no surges in power. Their strength was also appropriate to a machine made largely of wood.

Images prepared from a digital 3D model of an actual stone lifter. Modelling was in Amapi. Bryce rendered the images. Post production was in Adobe Photoshop. The interactive graphic was prepared in Adobe Flash.