Well safety valve

Abstract

In a well safety valve for controlling the fluid flow through a well tubing in which the valve closure means is controlled by a longitudinal movable tubular member, the improvement of a fail-safe mechanism for avoiding damage to the valve by avoiding excessive operating forces. The tubular member includes first and second telescoping sections which are releasably locked together in an intermediate extended position for normally opening and closing the valve on movement of the tubular member. The releasable locking means is sized to release upon the application of a predetermined force less than a force sufficient to cause damage to the valve whereby upon application of an excessive force the sections will telescope towards each other preventing damage to the valve. Tool engaging means are provided on the second telescoping section for repositioning the tubular sections relative to each other or for extending the second section for locking the valve closure member in the open position. A third section may be provided telescopically engaging the first section and positioned axially aligned above the second section in which one-way clutch means is provided between the first and third sections allowing downward movement of the third section relative to the first section with tool engaging means on the third section for moving the third section downwardly for engaging the second section and locking the second section in an extended lockout position.