Reinventing The Egyptian Pulley

by Stephen W. Blakely
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Photos and Illustrations

Full scale Egyptian Pulley, limestone, with 12 inch diameter roller, successfully tested duplicating a 5,000 pound weight lift (52 degree incline), is shown in below PHOTO.


The first four SKETCHES below show how the stone block on its wood sled would have been pulled up and unloaded at the top.  The first sketch is a simplified "cartoon" showing the basic operation of the Egyptian Pulley (but does not illustrate loading/unloading the stone).

Sketches two and three illustrate a likely stone unloading technique in which a locking "key," holding the Pulley in (horizontal) position, is removed as the stone/sled reaches the top edge. The stone/sled is then simply pulled over the edge and the Pulley transitions horizontally (in the direction the rope is pulled). 

Sketch four shows the use of a counterweight and two Egyptian Pulleys to lift the stones during the last stage of construction (with relatively little surface area on top).

Sketch five illustrates use of a second 
 Egyptian Pulley to achieve a 2:1 mechanical advantage.

Sketch six illustrates use of an Egyptian Pulley to achieve a 2:1 mechanical advantage (in addition to the Pulley changing the rope direction). Other variations to achieve a 2:1 mechanical advantage can easily be imagined, for example, the axis of the second Pulley could be vertical. 

Sketch seven is an illustration showing a grooved "rope roll" (approximately 13 inches axial length) found at the Step (Djoser) Pyramid.  The Step Pyramid predates the Great Pyramid by more than 100 years.


  
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