Selective torque operator for a valve

摘要

A low torque operator for selectively engaging a gear unit in an actuating drive stem of a valve having a collar with an axial bore and a slot through its side. The slot includes a projection directed towards an upper end of the collar and has an edge oriented oblique to the collar axis. A drive shaft inserts in the bore, and a pin mounted in the drive shaft engages the slot during low torque conditions. The operator also includes an idler gear and a bullgear. A driven shaft with two drive pins inserts into the bore on a lower side of the collar. The upper of the two pins remains in contact with a shoulder formed on a lower end of the collar during low torque conditions. The lower of the two pins engages a shoulder formed on a lower side of the bullgear during high torque conditions.

主权项

1. A valve for use in a wellhead assembly comprising:
a valve member that is stroked between open and closed positions by a rotatable shaft, the rotatable shaft having a drive member; a torque selecting device operably associated with the rotatable shaft having a low torque position and a high torque position, the torque selecting device comprising a slot with an outer edge that is engaged by the drive member a spring member mounted on the rotatable shaft for urging the torque selecting device into a position for rotating engagement with the rotatable shaft; and a gear member in selective engagement with the torque selecting device,
wherein, torque is coupled directly to the valve member through the rotatable shaft when the torque selecting device is in the low torque position; torque is coupled from the rotatable shaft to the valve member through the gear member when the torque selecting device is in the high torque position; and the torque selecting device is automatically shifted to the high torque position when torque applied to the rotatable shaft is sufficient to overcome a preset load of the spring member to slide the drive member along the outer edge to axially move the torque selecting device and the gear member.