GRABBING DEVICE FOR STUCK TOOL WITH VIBRATION ACTION Russian patent published in 2009 - IPC E21B31/20 

FIELD: oil and gas industry.

SUBSTANCE: invention refers to oil and gas industry, namely to grabbing devices for eliminating pipe breakages in wells. The device consists of a body with grabbing elements, a guiding surface and a longitudinal flushing hole, inclined planes which are located diametrically and offset along the body axis and equipped with protrusions made in the form of a dovetail, which are interconnected with slots of the appropriate shape of grabbing elements, and percussion mechanism and pulse generator which are located over the body one above the other. Percussion mechanism consists of a shell, a nipple arranged in the shell, a differential annular stock spring-loaded from below and installed between the shell and the nipple with the possibility of axial movements. Nipple is equipped with upper, intermediate and lower rows of radial holes and a blind transverse partition dividing upper and intermediate rows of radial holes, which, when in position, are connected to each other by means of a bypass channel provided between the shell and the nipple. The holes connecting, when in position, the space above the stock stage to the device external space are made in the shell opposite differential annular stock which in initial position overlaps the intermediate row of the nipple radial holes. The shell of percussion mechanism is connected rigidly and in axial alignment from above to pulse generator. The core is tightly installed in the casing and spring-loaded upwards with the possibility of restricted axial movement.

EFFECT: improving the device operating efficiency, decreasing the load on a pipe string.

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