| 摘要 |
The core barrel apparatus includes a wire line core barrel inner tube having a latch body main body portion and an inner portion threaded together to cooperatively provide a radial outer groove mounting a landing ring seatable on the drill string landing ring with the latches seatable in the drill string latch seat and a radial inner groove mounting a bushing surrounding the axial bore of the bypass channel for bypassing fluid between portions of the latch body on axial opposite sides of the latch body ring. The valving mechanism in the bore includes the bushing and may include a valve spring axially inwardly of bushing and a valve ball. The valve ball and bushing may be of a resiliency to permit the ball passing through the bushing under fluid pressure or prevent the ball passing through the bushing. Overcenter linkage connected to the latches is retractable by a retractor pin. In one embodiment the inner tube assembly may be of a fast descent type lowerable in a drill string by an overshot assembly having pulling dogs that remain in a coupled relationship to the inner tube assembly spearpoint until the latches move to their latch seated position and the dogs are forced by the spearpoint to a release position and thence the overshot release tube moves to retain the dogs in their release position and a second embodiment of an underground type. |
