Title page for ETD etd-01122007-164554

Document Type Master's Dissertation
Author Strydom, Johannes Petrus De Wet
URN etd-01122007-164554
Document Title Development of a vibration absorbing handle for rock drills
Degree M Eng (Mechanical Engineering)
Department Mechanical and Aeronautical Engineering
Advisor Name Title
Prof P S Heyns Committee Chair
Prof J C van Niekerk Committee Co-Chair
  • pneumatics technology
  • drilling and boring machinery
Date 2001-04-01
Availability unrestricted
Excessive vibration exerted on the human body can cause many harmful phenomena that can result in permanent bodily damage or permanent disability. Human vibration is classified into two main categories: Hand,arm vibration and whole,body vibration. Hand,arm vibration is vibration transmitted through a percussive tool handle via the hand,arm system to the rest of the body. The main diseases concerning hand,arm vibration are Vibration White Finger (VWF), neurological diseases in the hand and fingers and musculoskeletal diseases like carpal tunnel syndrome.

These diseases, especially VWF and musculoskeletal disorders, are mainly associated with lower frequencies. VWF in particular is more likely to occur when an operator is subjected to vibrations with high magnitudes in the 25-40 Hz region. The operating frequencies of most rock drills vary between 30 and 50 Hz. Although there are many other contributing factors like grip force, hand temperature and subject variability, prevalence of VWF among rock drill operators is relatively high in the world. The situation in South Africa is not yet very clear, and further research must be done to evaluate the current status of VWF in South Africa.

Vibration energy at higher frequencies can be attenuated with rubber grips or gloves, and these types of dampers are already available on the market. The problem concerning the operating frequency of the drill has not yet been successfully addressed, and thus remains a problem in the rock drill industry as it is at the moment.

The main objective of this thesis was the development and testing of a concept that can potentially be implemented on a rock drill to attenuate the operating frequency of a rock drill. The concept must be able to account for minor changes in operating frequency on a specific drill. In addition to that, the drill operating frequency varies from one drill to another. The thesis also aims to lay the mathematical foundation to design an attenuating handle for a specific drill with a specific operating frequency. All the objectives must be obtained without noticeable sacrifices in drill control or performance.

The thesis includes the concept generation, optimisation, design and manufacture of a rock drill vibration absorber. The absorber has been tested, and the results are presented.

2000 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.

Please cite as follows:

Strydom, JPdeW 2000, Development of a vibration absorbing handle for rock drills, MEng dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-01122007-164554/ >


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