Mechanical Engineering Exam: CAD & Design (Paper 2 – Design Written), Exams of Computer Aided Design (CAD)

Download Mechanical Engineering Exam: CAD & Design (Paper 2 – Design Written) and more Exams Computer Aided Design (CAD) in PDF only on Docsity! CORK INSTITUTE OF TECHNOLOGY Higher Certificate in Engineering in Mechanical Engineering – Award National Certificate in Engineering in Mechanical Engineering – Award (NFQ – Level 6) Summer 2005 CAD & DESIGN (Paper 2 – Design Written) Time: 2 Hours Answer Question 1 (40 marks) and two other questions (30 marks each) Examiners: Dr. R.K. McMullan Mr. J. Connelly Mr. R. Simpson (1) With regard to Service Factor: • Explain its meaning and how it influences drive-system specification • List the factors that influence its value • Give an example of a low and high service-factor application Regarding belt-drives, discuss the following: • Ease of installation • Service life / failure mode • Operating environment • Speed and torque limitations • Service life / failure mode • Versatility (15 marks) A single-cylinder 160cc 5.5H.P. engine, rotating at 400rpm, is used to drive a cement mixer for up to 6 hours each day. A chain-drive is required to step the speed down to 80rpm, before a worm-drive gearbox produces the required speed on the drum. The engine and gearbox shafts are spaced 300mm apart. The overall size of the chain-drive must not exceed 55cm. Design a chain-drive for the above application, using the tables provided. Clearly specify: • Service Factor • Chain size and pitch • Driven sprocket • Design Power • Number of strands • Lubrication method • Speed Ratio • Drive sprocket • Chain length (25 marks)