Abstract: A fan rotor is mounted on a shaft carried on bearings attached to a base plate and there is provided an assembly for preventing reverse rotation of the fan which could damage the motor. A stop plate is mounted on the base adjacent the shaft with an edge adjacent the shaft. A pair of wing members are carried on the shaft on two collar pieces so that each wing member is pivotal between ends of the collar pieces about an axis parallel to the tangent to the shaft at the wing member. The wing members are V-shaped and pivot so that one leg moves under gravity either in the vertical or horizontal orientations of the shaft from a retracted position, in which it is free from the stop plate to an extended position in which it engages the abutment surface of the stop member to prevent reverse rotation. The wing members are shaped and weighted such that rotation of the shaft beyond a predetermined angular velocity causes centrifugal force to move the wing members to the retracted position.

Abstract: A fan rotor is mounted on a shaft carried on bearings attached to a base plate and there is provided an assembly for preventing reverse rotation of the fan which could damage the motor. A stop plate is mounted on the base adjacent the shaft with an edge adjacent the shaft. A pair of wing members are carried on the shaft on two collar pieces so that each wing member is pivotal between ends of the collar pieces about an axis parallel to the tangent to the shaft at the wing member. The wing members are V-shaped and pivot so that one leg moves under gravity either in the vertical or horizontal orientations of the shaft from a retracted position, in which it is free from the stop plate to an extended position in which it engages the abutment surface of the stop member to prevent reverse rotation. The wing members are shaped and weighted such that rotation of the shaft beyond a predetermined angular velocity causes centrifugal force to move the wing members to the retracted position.

Abstract: An apparatus for use with motor-driven assemblies is described. The motor-driven assembly comprises a motor, a pulley driven by the motor, a driven element and a belt drive connecting the pulley and the driven element. The apparatus comprises a motor base and a pivot base. The motor is arranged on the motor base such that, due to the positioning of its mass, the motor will pivot away from the drive element. However, pivoting in this direction is opposed by the belt drive. Thus, as the belt drive tension reduces, the motor will pivot away from the drive element, thereby tightening the belt. A one-way restraining means connecting the pivot base and the motor base prevents the motor from pivoting back toward the drive element, thereby keeping the belt drive taut and retaining drive design expectations.