Research Papers

A Study on Possible Motors for Siege Towers

[+] Author and Article Information
Cesare Rossi1

 Università di Napoli Frederico II, Napoli 80125, Italycesare.rossi@unina.it

Stefano Pagano

 Università di Napoli Frederico II, Napoli 80125, Italystefano.pagano@unina.it


Corresponding author.

J. Mech. Des 133(7), 071009 (Jul 19, 2011) (8 pages) doi:10.1115/1.4004197 History: Received November 16, 2010; Revised May 05, 2011; Published July 19, 2011; Online July 19, 2011

This paper studies the motion of the ancient siege tower. Many considerations and different pieces from the classics strongly suggest that those war machines were powered by internal motors; for this reason, the authors examine some mechanical systems, all certainly used in the Classic Age, that could be easily adopted to power the siege towers. This war machine was first used in Europe by Greek engineers and called Helepolis (ε`λε´πoλις, “taker of cities”); however, there are earlier examples of siege towers built in Mesopotamia. First of all, some pieces from Classic authors have been reported in which it is possible to find several traces on what we propose. Then some possible ancient motors suitable to be installed into the helepolis are proposed: capstans, tread wheel motors like the ones used by the Greek-Roman cranes, and counterweight motors. The proposed motors are also analyzed from a mechanical point of view in order to examine, at least theoretically, their effectiveness in such applications. Results obtained by a simulation with a Working Model 2D™ model showed that the proposed device is certainly possible and also suitable and effective.

Copyright © 2011 by American Society of Mechanical Engineers
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Figure 1

Assyrian bas-relief showing a siege tower, 865–860 BC

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Figure 2

Authors’ helèpolis pictorial reconstructions [4]

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Figure 7

Pictorial reconstruction of tread wheels for Helèpolis’ propulsion [4]

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Figure 8

Virtual reconstruction of the device to lift the curtains and a particular of the telescopic elements [4]

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Figure 9

Counterweight motor of Heron’s self propelled automata [6]

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Figure 10

Mechanism to change direction [6]

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Figure 3

Scheme of the mechanical device to apply the motor torque to the wheels axle

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Figure 4

Scheme of the capstan

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Figure 5

Authors’ pictorial reconstruction of the possible propulsion system by capstans [4]

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Figure 11

Traction with independent axle shafts [11]

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Figure 12

Scheme of rope rolling to program the motion

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Figure 13

Scheme of the helepolis’ counterweight motor

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Figure 14

Helepolis’ with counterweight motor WM2D model

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Figure 15

Simulation results at constant counterweight velocity

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Figure 16

Simulation results at changing counterweight velocity




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