safety hazards associated with operating this machinery in the most preferred embodiment drum 117 has six sides 150 152 154 156 158 and 160 arranged in a spiral type arrangement that are particularly configured to receive drive carriages 38 it is noted that a drum with fewer than six could work within the scope of the present invention however a six sided structure is considered the preferred embodiment preferably each of these sides is arranged 60 degrees apart from each other six is considered the optimal number of sides for the drum so that the carriages are pushed out across the surface rather than down into the floor the six sided structure reduces the torque on the carriages to move them it is noted that an alternative number of sides can be used if desired the 6 sides define and increasing radial distance relative to the axis defined by the drum shafts such that the last end of the sixth 39 s side is spaced radially from the first end of the first side by a set radial instance radial distances are equal to the thickness of the drive carriages each of the sides of a drum 150 152 154 156 158 and 160 has an equal length each carriage has a push plate or a u201c drum engagement plate 302 u201d for engaging the drum these drum engagement plates are positioned at a force absorbing angle so that the drum can engage the carriages to pull the drive carriages around the drum thereby retracting the bench system the drive carriages are interconnected using hinges 300 forming a continuous series of interlinked drive carriages the hinges 300.