Abstract: A counterbalanced vertical track assembly which may be configured with three types of pulley support assemblies are herein disclosed. The first type of pulley support assembly has a pair of opposed pulley modules having an elongate structural element interposed the two pulley modules which are attached to end plates at both ends of the elongate structural element. The second type of pulley support assembly has a pair of opposed pulley modules which include male end connectors for demountable engagement of the pulley modules with another module of the system with female ends. The third type of pulley support assembly has a pair of opposed pulley modules wherein the modules' pulley brackets are repositionable to varying angular orientations by alternating screw mount positions selected on mount components at opposite ends of an elongate structural element.

Abstract: A kit of portable modular components for use in demountably configuring a variety of structural assemblies. The kit comprises three types of elongate structural support components wherein the first type has a pair of opposed male ends, the second type has a male end and an opposed female end, and the third type has a pair of opposed female ends, wherein the male ends are configured for demountable engagement with the female ends. Each of the male ends comprises a cylindrical body with at least one linear set of two spaced-apart prongs around the circumferential surface of the cylindrical body. Each of the female ends has a cylindrical receptacle with one or more linear channels for receiving therein the cylindrical body and the at least one linear set of prongs. The female ends are provided with locking assemblies for releasable engagement the male ends.