CENTRIFUGAL BACKSPIN RETARDER AND DRIVE HEAD FOR USE THEREWITH
摘要
A backspin retarder for a shaft comprises a brake mechanism including a stationary brake member and opposed brake members rotatable with the shaft and movable between braking position in which the movable brake members engage the stationary brake member and a non-braking position in which the movable brake members are removed from the stationary brake member and a brake control mechanism responsive to the direction of rotation of the shaft for disabling the brake mechanism when the shaft rotates in a forward direction and for enabling the brake mechanism when the shaft rotates in a reverse direction.
申请公布号
WO9958869(A1)
申请公布日期
1999.11.18
申请号
WO1999CA00394
申请日期
1999.05.12
申请人
WEATHERFORD CANADA LTD.;HULT, VERN, ARTHUR;BLUNDELL, CURTIS, CHRISTOPHER