Safety guard for a rotatable member

摘要

Embodiments of a safety guard, fit concentrically over a rotating member, such as a rod assembly, which extends outwardly from apparatus, such as a drive head. The guard may be restrained during normal operation for preventing entanglement of personnel or other apparatus with the rod assembly which continues to rotate within the tubular guard, or may be unrestrained during normal operation. When unrestrained, the guard is free to co-rotate with the rod assembly, but has a low moment of inertia such that the guard decelerates rapidly when restrained so as to prevent entanglement. An anti-friction interface between the guard and the rod assembly is formed by the material of manufacture of the guard itself or by bearings or bushings supported in an annulus between the guard and the rod assembly.

主权项

1. A system for preventing entanglement by contact with a rotating rod assembly for driving a downhole pump, the system comprising:
a drive head having a housing from which the rotating rod assembly extends, the rod assembly comprising a rotating rod and a rod clamp for operatively connecting the rotating rod to a main driven shaft extending upwardly from the housing and being rotatable therewith; and a tubular guard positioned concentrically about the driven member, forming an annulus therebetween, the guard having a moment of inertia; and an anti-friction interface within the annulus for enabling differential rotation between the guard and the driven member, when, during normal operation, the safety guard is unrestrained, the guard is free to co-rotate with the driven member; and when restrained by contact therewith, the moment of inertia enables rotation of the guard to cease rotation while the driven member continues to rotate therein.