초록 ▼

There is disclosed an actuator for a rotary valve, such as a butterfly valve which rotates a quarter of a turn between open and closed positions. The actuator includes a drive mechanism releasably attachable to the stem of the valve for rotating it in response to operation of a reversible electric m

There is disclosed an actuator for a rotary valve, such as a butterfly valve which rotates a quarter of a turn between open and closed positions. The actuator includes a drive mechanism releasably attachable to the stem of the valve for rotating it in response to operation of a reversible electric motor.

대표청구항 ▼

[ What is claimed is:] [1.] A rotary valve actuator, comprisinga housing adapted to be mounted on the valve,a worm gear mounted for rotation in the housing and adapted to be connected to the valve stem, when the housing is mounted on the valve, for imparting rotation thereto,a reversible electric mo

[ What is claimed is:] [1.] A rotary valve actuator, comprisinga housing adapted to be mounted on the valve,a worm gear mounted for rotation in the housing and adapted to be connected to the valve stem, when the housing is mounted on the valve, for imparting rotation thereto,a reversible electric motor in the housing having an output shaft,a worm shaft mounted for rotation and limited axial movement in opposite longitudinal directions within the housing,means connecting the motor to the worm shaft for rotating the worm shaft in opposite rotational directions responsive to reverse operation of the motor,an assembly including a worm and a cam having longitudinally spaced cam surfaces mounted on the worm shaft for rotation and axial movement therewith and with the worm shaft engaged with the worm to rotate the worm gear and thus the valve stem,spring means surrounding the worm shaft and compressed between the housing and each end of the assembly, andfirst means on the housing and engageable by a first cam surface, when one of the spring means is compressed to permit the worm shaft and cam to move longitudinally in one direction a predetermined extent, in order to deactivate the motor in response to a predetermined torque due to obstruction to rotary movement of the valve stem in one rotational direction, andsecond means on the housing and engageable by a second cam surface, when the other spring means is compressed to permit the worm shaft and cam to move longitudinally in the opposite direction a predetermined extent in order to deactivate the motor in response to a predetermined torque due to obstruction to rotary movement of the valve stem in the opposite rotational direction.