The University of Manchester

The School of MACE

Mechanical Engineering Design I

Semester 2013-2014

Design of a Silent Hand-held Jackhammer

Student Name: Lengshan Wang

Student ID: 9121060

Group 13

Coordinator : Dr Olutunde Oyadiji Lecturer(s): Prof Sri Hinduja, Dr Mohammad Sheikh

Submission Date: 16/12/2013

Abstract

The present designs relate to a various devices added to the jackhammer or an inner structural change, whose purpose is to reduce the jackhammer's noise when working. In general, there are three types of jackhammers which are air-cycle system jackhammer, jackhammer with air channel composed of unbendable metal, adding an energy-absorbing jacket cover over the housing of the jackhammer and substituting the original material of piston with Mn-Cu alloy. Three different conceptual and embodiment design will be displayed in the report.

Jackhammers were originally developed for the needs of mining, quarrying, excavating , tunneling, and many other percussions. The first prototype was created in 1848 by Dr.

Jonathan Couch (1789-1870) . In this drill, the drill bit passed through the piston of a steam engine. However, i n 1850, Couch's assistant, Joseph W. Fowle, optimized the jackhammer by using compressed air to drive the drill bit, which making the first true pneumatic jackhammer come into the world.1. Background

Dr. Jonathan Couch (1789-1870)

A hand-held jackhammer is typically a percussive drill commonly powered by compressed air. It has two handles on one end and a chisel-like bit on the other that rapidly jabs up and down to break up concrete, rock, or other materials. Inside, it has many components such as piton, value, etc. Fig. 1 shows the internal structure of a jackhammer. The tool is connected to a separate d air-compressor unit powered by a diesel engine by a pneumatic hose , which has to be made of especially thick plastic , carries high-pressure...