Definitions for "Single Purchase"
A manual rigging system where the pipe battens travels the same distance as the counterweight arbor. In a single purchase system the counterweight should be equal to the weight supported on the pipe batten. Every foot of travel in the counterweight arbor and control line equals a foot of travel at the pipe batten.
A method of lifting items where an equal load is located onstage and offstage to create a balanced system.
A counterweight system where the cradle travels the same distance as the bar.
Keywords:  lifetime, whole, great, school, family
a great practical investment for the whole family for a whole school lifetime