A belt-tensioning device includes an electric machine having a drive belt pulley, which is driven about a drive axis, and a further drive belt pulley, where an endless belt wraps around the drive belt pulleys. The device has a housing in which a first and a second spring arm are mounted, in each of which spring arms a tension roller having axes of rotation which are parallel to the drive axis is rotatably mounted. The spring arms are supported against one another and press the endless belt together via the tension rollers in the region of the drive belt pulley. A first and a second further spring arm are provided adjacent to the spring arms which are adjustable by an adjustment element such that the spring forces of the further spring arms either do or do not support the spring forces of the spring arms acting on the endless belt.

A work machine having a belt tensioning system is described. A belt is engaged with an engine drive sheave and a driven sheave of a rotor having a plurality of cutting tools configured for reducing wood infeed material. An idler pulley is mounted to an idler arm that is hinged to the machine frame. An actuator is hinged to the idler arm and the frame. The actuator may be extended and retracted in order to press the idler pulley into stronger and weaker engagement with the belt in order to set the desired amount of tension in the belt. One or more sensors may be used to sense the amount of tension in the belt, and the one or more sensors may be in communication with a control system that controls the actuator to monitor and adjust the belt tension so that it is maintained within desired limits.

A method of operating a chain drive that includes sprockets. Tensile chain moments on the sprockets are determined and a specification value for operating the chain drive is determined therefrom in an automated manner. A corresponding assembly has a chain drive with sprockets and with a control device at least partly associated with the chain drive. The control device is configured for carrying out the method and a specification value for load distribution among the two drives for operating the chain drive is determined therefrom in an automated manner.

A yard maintenance device having a working assembly selectively rotatable based on operation of an engine of the device may include a belt drive system. The belt drive system may include at least one driven pulley operably coupled to the working assembly, a drive shaft operably coupled to the engine, a drive belt configured to selectively couple the drive shaft to the at least one driven pulley, a tension adjustment assembly, and a control unit. The tension adjustment assembly may be configured to operably couple to at least one component of the belt drive system to adjust a position thereof to modify tension of the drive belt. The control unit may be configured to provide electronic control of the tension adjustment assembly.

A method of operating an accessory drive system for a motor vehicle, wherein the accessory drive system includes one or more accessory components, a motor generator of the motor vehicle, and a flexible drive element configured to transmit a torque load between the one or more accessory components and the motor generator, includes determining a maximum permissible flexible drive element torque threshold, detecting an increase in torque demand on the flexible drive element, determining when the torque demand on the flexible drive element will exceed the flexible drive element torque threshold, and reducing the torque demand of one or more of the accessory components so that the flexible drive element torque threshold is not exceeded.

Systems, apparatus, and methods for tensioning systems of a drive belt are disclosed. Particularly, tensioning systems for a drive belt of a rotary screen of a harvester combine are disclosed. The tensioning system provides for avoiding over-tensioning the drive belt when the drive belt is disengaged from a drive shaft. The tensioning system may also provide for maintaining continuous operation of the drive shaft as the drive belt is moved between engagement and disengagement with the drive shaft.

A method of operating an accessory drive system for a motor vehicle, wherein the accessory drive system includes one or more accessory components, a motor generator of the motor vehicle, and a flexible drive element configured to transmit a torque load between the one or more accessory components and the motor generator, includes determining a maximum permissible flexible drive element torque threshold, detecting an increase in torque demand on the flexible drive element, determining when the torque demand on the flexible drive element will exceed the flexible drive element torque threshold, and reducing the torque demand of one or more of the accessory components so that the flexible drive element torque threshold is not exceeded.

Systems, apparatus, and methods for tensioning systems of a drive belt are disclosed. Particularly, tensioning systems for a drive belt of a rotary screen of a harvester combine are disclosed. The tensioning system provides for avoiding over-tensioning the drive belt when the drive belt is disengaged from a drive shaft. The tensioning system may also provide for maintaining continuous operation of the drive shaft as the drive belt is moved between engagement and disengagement with the drive shaft.

A tracked vehicle, in particular a construction machine, more particularly a road construction machine, with at least one drive motor and a travel pump of a travel drive hydraulic circuit, which is driven by the drive motor, for generating a drive pressure; at least one track unit, said track unit comprising a drive wheel driven via the travel drive hydraulic circuit, at least one guide wheel, a track endlessly running around the drive wheel and the guide wheel, as well as a track tensioning apparatus for tensioning the track, and the track tensioning apparatus comprising an adjusting device with a track tensioning hydraulic cylinder with which the distance between two wheels of the track unit, in particular the drive wheel and the guide wheel, is adjustable for tensioning the track, the track tensioning hydraulic cylinder being connected via a hydraulic tensioning line to a hydraulic pretensioning source via which it can be loaded with an initial pretensioning pressure. The tensioning apparatus further has a damping device with a spring for damping pressure peaks in the adjusting device. A method for operating a tracked vehicle with a track unit.

In a pulley apparatus, belt supporting portions of belt support pieces, which support a belt from a radially inside thereof, are arranged along a circumferential direction of a power shaft and each have a predetermined circumferential length. In a pulley driven mode, the belt support pieces rotate about corresponding first supporting members in a direction making the belt supporting portions become closer to the power shaft with second supporting members being relatively moved in corresponding elongated holes toward radially outer ends thereof, causing the belt supporting portions to be reduced in radius. In a pulley driving mode, the belt support pieces rotate about the corresponding first supporting members in a direction making the belt supporting portions become further from the power shaft with the second supporting members being relatively moved in the corresponding elongated holes toward radially inner ends thereof, causing the belt supporting portions to be increased in radius.