block and tackle

[derekleffew]

A series of pulleys over which rope is passed to attain a mechanical advantage.

From Integrated Publishing - Educational Training Manuals

In a tackle assembly, the line is reeved over the sheave(s) of blocks. The two types of tackle systems are simple and compound. A simple tackle system is an assembly of blocks in which a single line is used (view A of figure 4-19). A compound tackle system is an assembly of blocks in which more than one line is used (view B of figure 4-19).