Abstract: A latching device for locking and removal of a flow control device from a mandrel receiver comprises a cylindrical stem, a locking sleeve slidably mounted upon the stem, an annular locking ring mounted for a limited axial movement along the lower portion of the locking sleeve and a compression spring. The annular locking ring has upper and lower bevel surfaces which are complementary to bevel surfaces of a mandrel receiver.an improved retrieval device is disclosed for retrieval of a valve which is locked within the mandrel receiver, the device comprising a cylindrical body having a central opening and an internal wall with a recess and a retrieval tool provided with a compressible C-shaped ring for locking engagement with the recess formed in the cylindrical body, thereby allowing retrieval of the cylindrical body, along with the well tool which is securedly attached to the retrieval device.

Abstract: An arch bar for direct bonding to the teeth of a patient comprises an elongated arch bar having a plurality of ligature hook elements extending from one side thereof. The back or gingival portion of the arch bar is provided with a layer of mesh material extending substantially the entire length thereof. The mesh material may be in the form of a fine metal mesh which is spot welded or otherwise secured to the gingival portion of the arch bar to effect optimum retention with the bonding agent that secures the arch bar to the enamel surfaces of the patient's teeth. The arch bar may be perforate along its length to enable light passage through the arch bar when photo polymerizing bonding agents are employed. The ligature hooks may be of a configuration to enable retention thereof by special application instruments for positioning of the arch bar during installation.

Abstract: A downhole flow testing valve having a tubular housing with a valve and flow tube movable within the housing between an open position where valve ports therein are positioned in registry and a closed position where the valve ports are out of fluid communicating registry. The valve and flow tube is closed by a resultant force developed by compressed gas and opened by pressure introduced into the valve from the annulus between the valve and well casing. The normally closed flow testing shuttle valve is secured in its closed and safe condition during installation by a hydraulically locked sleeve valve. Upon fracture of a break plug by an implement dropped through the straight through flow passage of the flow tube hydraulic fluid captured within a locking chamber is released from the locking chamber by the force of a compression spring.