Heron of Alexandria in his study listed the five mechanisms as the lever, windlass, pulley, wedge, and screw, which were known to set a load in a motion. Flemish engineer Simon Stevin derived the mechanical advantages of the inclined plane that was merged with the simple machines. Leonardo da Vinci also contributed to the study of machines by discovering the classic rules of sliding friction.
A stable work platform, suited to the nature of the work that allows for good posture relative to the work performed, sure footing, safe environment and fall prevention (if a fall may occur), is a basic requirement. For example, cooling towers on building roofs may have poor access, yet must be attended by a service person at predictable times for water treatment, chemical dosing or monitoring of automated dosing equipment.
Access needs can be predicted and planning must occur in advance. People need access to machinery and equipment in the workplace (either continually or occasionally) for predictable tasks such as operation, maintenance, repair, installation, service or cleaning.
A simple machine is a device that simply transforms the direction or magnitude of a force. It is a tool that consists of one or more parts, and uses energy to meet a particular goal. The evolution of machines started with the beginning of Industrial revolution, and brought changes in the fields of agriculture, manufacturing, mining, transportation, and technology, due to which there was a profound effect on the social, economic and cultural conditions of the times.