An air-cooled heat exchanger has a frame assembly, a plenum supported by the frame assembly, an engine and a fan assembly. The engine includes a drive shaft and the fan assembly includes a fan connected to a fan shaft. The fan assembly is configured to move air through the plenum. The air-cooled heat exchanger also includes a drive assembly connected between the engine and the fan assembly. The drive assembly has a fan shaft sheave connected to the fan shaft, a driver sheave connected to the drive shaft, an idler pulley, and a drive belt in contact with the fan shaft sheave, driver sheave and idler pulley. The air-cooled heat exchanger has an idler bearing adjustment mechanism that is configured to adjust tension on the drive belt by adjusting the position of the idler pulley relative to the drive belt.

A belt tensioning device for a crusher or a screening machine for tensioning at least one circulating drive belt which is deflected about a belt pulley of a drive and has a load strand and an empty strand. The drive can be driven with a crushing assembly, a screening unit, a generator, or the like of the crusher by the drive belt. The vibrational stress acting on the machine chassis can be significantly reduced in that the belt tensioning device has two tensioning rollers each of which is rotatably mounted on a holder of a tensioning part. One tensioning roller is paired with the empty strand and the other is paired with the load strand. Additionally, the two tensioning parts can be adjusted relative to each other between an open position and a tensioning position, in which the tensioning parts are held against each other at least opposite the tensioning direction. In particular the tensioning parts can be blocked against each other, and the complete closed system can be freely moved linearly using adjustment guides according to the load situation.

The invention relates to a belt tensioning device for a crusher or a screening machine for tensioning at least one circulating drive belt (20) which is deflected about a belt pulley (12) of a drive (10) and has a load strand (21) and an empty strand (22). The drive (10) can be driven with a crushing assembly, a screening unit, a generator, or the like of the crusher by means of the drive belt (20). The vibrational stress acting on the machine chassis can be significantly reduced in that the belt tensioning device has two tensioning rollers (47), each of which is rotatably mounted on a holder (41, 51) of a tensioning part (40, 50). One tensioning roller (47) is paired with the empty strand (22) and the other is paired with the load strand (21). Additionally, the two tensioning parts (40, 50) can be adjusted relative to each other between an open position and a tensioning position, in which the tensioning parts are held against each other at least opposite the tensioning direction, in particular the tensioning parts can be blocked against each other, and the complete closed system can be freely moved linearly using actuators (44.2) according to the load situation.