| 摘要 |
Slips (1, 21, 41) for engaging any jointed, coiled or flexible tubular with substantially no scoring, gouging or scraping, such as when supporting a dri ll string in a borehole or gripping a tubular (2, 22) during the connection or disconnection of a tool joint or pulling a cable or pipeline; additionally, applying a pre-determined minimum gripping force in order to avoid rotary slippage when the weight of the string is insufficient to achieve a conventional slips action; additionally, including a coarse wedge (30, 50) t o take up the extra travel of a worn tool joint or a tubular of smaller diameter, with a means to ensure that the coarse wedge acts before the fine wedge (29, 49) does and a means to ensure that the wedging action remains if the actuating force is removed; additionally, including a secondary slips (4 0) to interfere with the upset on the tool joint to avoid relying on friction t o support the string and a means of integrating this with the gripping slips a nd ensuring that the secondary slips act first; additionally, the application o f these attributes 'upside down' to achieve the action of snubbing when forcin g a tubular into compression instead of tension for any reason.
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