the desired tension in the belt. A belt conveyor generally have a screw-type (mechanical) or a gravity-type counterweighted take-up unit, also termed as belt tensioning device.
In the screw-type take-up, the bearing blocks for the tail end pulley are located in guide ways, so that these may be moved by rotating two screws as and when belt tension needs to be increased.
In gravity take up, the tail end pulley is mounted on a movable carriage which is pulled
backwards along the length of the conveyor by a vertically hanging counterweight connected through a steel rope and deflecting pulleys. In an alternate design, the return side of the belt passes by the bottom of a counter-loaded deflictor roll which is free to move down to keep the belt taught.
Fig. 6.1.9 illustrates the two gravity take-up arrangements.