Strip-chart recording apparatus

Claim 1

A strip-chart recording apparatus for recording the value of a condition on a strip-chart of the type having a series of equally spaced sprocket holes at each side thereof and which is supplied in a compactly folded stack comprising, in combination: a supply basket adapted to receive said compactly folded stack, a surface aligned with said supply basket to support said stripchart as it is unfolded from said stack, said surface being flat in a direction transverse to the movement of said strip-chart and convex in direction of said movement, a chart roll having its axis of rotation aligned parallel to said flat surface and spaced a distance in the direction of said movement from the end of said surface whereby a section of said strip-chart is suspended between said end and the poiNt of contact with said chart roll, said chart roll having sprocket teeth at each end thereof adapted to engage said series of equally spaced sprocket holes in said strip-chart. means for rotating said chart roll at a uniform speed, a tensioning device biased to exert a force between said stripchart and said surface at a distance from said end whereby said force and the friction of said strip-chart in contact with said convex surface resists the pull of said sprocket teeth as said chart roll rotates, thereby providing sufficient tension to hold the suspended section of said strip-chart in its unfolded condition substantially flat, and pen means adapted to record on said suspended section of said strip-chart.