Abstract: Flexible couplings are provided comprising a male member disposed within a female member in a spaced apart configuration, with the space being filled, at least partially, with an elastically deformable material. The male and female members comprise features that prevent separation from one another after the elastically deformable material is provided in the space between them. For example, the male and female members of one embodiment each comprise a threaded region, with the respective male and female threads being intermeshed but generally spaced apart from each other. At least one of the male and female threads is tapered in two opposing directions with respect to a coupling centerline. The double taper requires the elastically deformable material to be displaced for the male and female members to become separated. However, the elastically deformable materials are constrained by surfaces of the male and female members, and therefore, cannot be displaced.

Abstract: A latching system for maintaining the position of a component within a downhole drill string section during operation of a drill string. One preferred latching system embodiment has a shoe member including a cavity for receiving a component, a chamber opening into the shoe member cavity, an engagement member movable in the chamber between a retracted position and an engagement position, a first passage in fluid communication with the chamber and extending to an end surface of the shoe member, and a second passage extending from an outer side surface of the shoe member to the first passage. A pressure differential between pressure in the first passage and pressure in the second passage alters the position of the engagement member.