US 5,551,510 A · Safety coupling for rotary down hole pump

Abstract

A safety coupling for preventing backspin at excessive speeds of a torque transmitting drive powering a drive shaft which stores reactive torque due to torsional stress is disclosed. The safety coupling includes a rotatable driving member to be coupled with a torque producing power source, a rotatable driven member to be coupled with the drive shaft for axial rotation therewith, a support structure for coaxially and rotatably supporting the driving and driven members in relation to each other, a radial abutment provided on the driving member, and a centrifugal force responsive pawl pivotally mounted to the driven member for releasable engagement with the abutment. The pawl is pivoted from a locking position wherein it engages the radial abutment upon mutual rotation of the driving and driven members to provide a positive driving connection therebetween, to a disengaged position wherein the driving and driven members are freely rotatable relative to each other by the centrifugal force acting thereon when the driven member is coupled to a drive shaft backspinning at a speed in excess of a selected speed. The coupling substantially prevents damage to the torque transmitting drive upon excessive back-spin of the drive shaft and reduces the risk of injury to personnel working in the vicinity of a drive shaft subject to elastic torsion.

Claims19

Dependent claims

A safety coupling for preventing backspin at excessive speeds of a torque transmitting drive powering a drive shaft which stores reactive torque due to torsional stress, the drive shaft normally being rotated in a forward direction by the torque transmitting drive, and backspin of the drive shaft being caused by the release, upon interruption of power to the drive shaft, of reactive torque stored in the drive shaft due to elastic torsion of the shaft, the safety coupling comprising,

a rotatable driving member to be coupled with a torque producing power source;
a rotatable driven member to be coupled with the drive shaft for axial rotation therewith;
means for coaxially and rotatably supporting the driving and driven members in relation to each other;
a radial abutment provided on the driving member;
and
a centrifugal force responsive pawl pivotally mounted to the driven member for releasable engagement with the abutment, the pawl being pivotable between a locking position wherein it engages the radial abutment upon mutual rotation of the driving and driven members to provide a positive driving connection there between, and a disengaged position wherein the driving and driven members are freely rotatable relative to each other;
the pawl being shaped and constructed to be moved from the locking position to the a disengaged position by a centrifugal force acting thereon when the driven member is coupled to the drive shaft and the drive shaft is backspinning at a speed in excess of a selected speed.

4 more elements

A safety coupling assembly for a rotary downhole pump rotated in a forward direction by a drive string rotatably suspended from a drive head and subject to elastic torsion, comprising

a drive spindle coupled with the drive string and axially rotatable therewith;
a rotatable driving member coupled with a torque producing power source and coaxially mounted to the drive spindle for axial rotation in relation thereto;
and
a one-way, non-slip centrifugal clutch for providing a driving connection between the driving member and the drive spindle when the drive spindle is rotated in the forward direction and for automatically disconnecting the driving member from the drive spindle when the drive string is backspinning in the opposite direction and at speeds in excess of a selected speed upon interuption of power to the driving member and subsequent release of the elastic torsion stored in the drive string.

1 more element

Dependencies are inferred from the claim text.

Safety coupling for rotary down hole pump

Life of this patent

Safety coupling for rotary down hole pump

Life of this patent

Abstract

Claims19