Abstract: An assembly for maintaining tension in a drive belt features a housing mounted on a base. The housing contains a biasing element that exerts torque on the housing to bias the housing. An arm is connected to the housing and rotates with the housing in response to the bias of the biasing element. A pulley is connected to the lever arm and engages a drive belt in response to the bias force of the biasing element on the lever arm. The pulley deflects the shape of the belt to provide tension in the belt. In one embodiment, the device includes one or more biasing elements that in a relaxed state have a curved configuration to correspond to the curved configuration of compartments in the housing.