Mechanisms an introduction

Mechanisms an introduction
Introduction
A mechanism considered to be an assembly of mechanical items designed to achieve a specific purpose within a machine. There are clearly an infinite number of mechanisms available but the notes and links are concentrating on the specific ones as listed below.

Motion Control Using Computers
The notes below relate generally to mechanical methods for providing relative motion and forces. There is an increasing tendency to produce motions using servo hydraulic systems and stepping motors under the control of digital computers. Although the mechanism design often requires creativity and a high level of analysis the final product is often low priced and provides reliable, efficient, predictable performance. However a mechanism is generally made to perform a fixed operation, reliably and predictably. Computer controlled motions can be continuously monitored and if necessary modified. If the output motion is changed from a harmonic motion to a periodic square wave motion or a sawtooth motion then changing the control parameters for a computer controlled system is often very convenient. If a large number of systems have been developed then the cost of modifying the software or firmware is much less than modifying a large number of mechanisms..

Although the motions of many of high technology machines and computer systems are being controlled by computers. The need for mechanisms is also increasing in consumer goods e.g. mechanisms in consumer goods, toys, lifting equipment, vehicles, aircraft, industrial machines, gardening implements,etc etc etc... ......


Classification Of Mechanisms
There are many methods of classifying mechanisms. The following list is a functional list based on the type of motion required. This list is based on that provided in Theory of Machines and Mechanisms ..Uicker, Pennock, and Shigley. The notes below are low level descriptions. Additional notes will be included soon..
1. Snap-Action Mechanisms
2. Linear Actuators
3. Fine Adjustment Mechanisms
4. Clamping Mechanisms
5. Location Devices
6. Ratchets
7. Escapements
8. Indexing Mechanisms
9. Swinging or Rocking Mechanisms
10. Reciprocating Mechanisms
11. Reversing Mechanisms
12. Couplings and Connectors
13. Sliding Connectors
14. Stop Pause and Hesitation Mechanisms
15. Curve Generators
16. Straight Line generators
17. Tracing Mechanisms