Patent ID: 6253844
Filing Date: 2001-07-03
Classification: E21B,F04B

Abstract:
A swivelling device adapted for connection to a drive string of a downhole rod pump, the device comprising;a housing having an opening at a bottom end, and having means for attachment to an external support at a top end, said means for attachment to said external support being rigidly fixed to said housing without possibility of relative movement there between;a rotatable shaft having most of its length housed within the housing, and extending through the opening and projecting only from the bottom end of the housing, the shaft including an integral means for attachment to the drive string at a bottom end of the shaft, said shaft and said means for attachment to the drive string being substantially symmetrical about a common axis of rotation and being such that said means for attachment to the drive string connects to said drive string with no point of articulation between the shaft and the drive string; andmeans for mounting the shaft rotatably within the housing, the means for mounting being enclosed within the housing.