Invention Grant
US5836388A Flexible joint for downhole tools 失效
井下工具柔性接头

Flexible joint for downhole tools
Abstract:
A downhole measurement tool is lowered into a well through a drill pipe. The tool has at least two modules which are joined by a flexible linkage. The linkage has two subs, each of which has an electrical connector for the modules. Each sub has a hub that is threaded. A threaded retainer nut retains each connector. Each nut has a hub that is threaded and is smaller in diameter than the sub hub. A coiled inner spring threadingly engages each nut hub. A coiled outer spring surrounds and threadingly engages each sub hub. The outer spring surrounds the inner spring and is wound in an opposite direction of the inner spring. The springs are embedded within an elastomeric member. The inner spring is dimensioned such that, for a selected lateral bend prior to installation with the outer spring, the inner spring will twist a selected angle in a first twist direction. Similarly, the outer spring is dimensioned such that for the selected lateral bend, prior to installation with the inner spring, the outer spring will twist substantially the same as the selected angle, but in a direction opposite to the first twist direction so as to cancel any twist between the subs once installed and subjected to a lateral bend. When the tool encounters a curved portion of the well, the inner spring, outer spring and elastomeric member flex to improve the navigability of the tool through the curved portion.
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